Virus-like particles comprising composite capsid amino acid sequences for enhanced cross reactivity

ABSTRACT

The present invention provides polypeptides having a composite amino acid sequence derived from a consensus sequence representing the capsid proteins of two or more circulating strains of a non-enveloped virus. In particular, the invention provides virus-like particles comprising at least one composite polypeptide. Such virus-like particles have antigenic epitopes of two or more circulating strains of a non-enveloped virus and produce an increase in antisera cross-reactivity to one or more circulating strains of the non-enveloped virus. Methods of making composite virus-like particles and vaccine formulations comprising composite virus-like particles are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of International ApplicationNo. PCT/US2009/053249, filed Aug. 10, 2009, which claims the benefit ofU.S. Provisional Application No. 61/087,504, filed Aug. 8, 2008, andU.S. Provisional Application No. 61/218,603, filed Jun. 19, 2009, all ofwhich are herein incorporated by reference in their entireties.

DESCRIPTION OF THE TEXT FILE SUBMITTED ELECTRONICALLY

The contents of the text file submitted electronically herewith areincorporated herein by reference in their entirety: A computer readableformat copy of the Sequence Listing (filename:LIGO_(—)022_(—)02US_SeqList_ST25.txt, date recorded: Feb. 8, 2011, filesize 120 kilobytes).

FIELD OF THE INVENTION

The invention is in the field of vaccines, particularly vaccinescomprising virus-like particles with a composite amino acid sequencederived from a consensus sequence representing two or more capsidproteins from non-enveloped viruses. In addition, the invention relatesto methods of preparing vaccine compositions and methods of inducing aprotective immune response using the vaccine compositions of theinvention.

BACKGROUND OF THE INVENTION

The prevalent approach to preparing vaccines for viruses with seasonalor year-to-year patterns is modeled by commercial Influenza vaccineswhich require the anticipation, publication, and subsequent synthesis ofa new vaccine when the virus evolves to present a different antigenicprofile. This approach causes significant timeline delays and cost asnew antigens are synthesized in anticipation of the next years viralstrain. Further, as evidenced by the failings of the 2008 influenzavaccine, errors in the predicted strain can result in significantdisease related costs as patients are under-protected. Thus, improvedmethods for designing and preparing vaccines to protect against multiplecirculating strains of disease-causing virus is desirable.

Noroviruses are non-cultivatable human Caliciviruses that have emergedas the single most important cause of epidemic outbreaks of nonbacterialgastroenteritis (Glass et al. (2000) J Infect Dis, Vol. 181 (Sup 2):S254-S261; Hardy et al. (1999) Clin Lab Med, Vol. 19(3): 675-90). Theseviruses have been grouped into five different genogroups of whichgenogroups I and II are further subdivided into greater than 25genotypes and are the agents for the vast majority of illness in humansattributed to this virus. There are significant challenges to thedevelopment of vaccines against Norovirus, including the inability topropagate the virus in culture and suitable animal models of acutegastroenteritis. Standard virologic techniques including viralattenuation or in vitro neutralization assays are therefore not possibletoday.

Noroviruses contain a 7.5 Kb single strand positive sense RNA genomethat contains three open reading frames. The major viral capsid protein(VP1) is encoded by ORF2 and expression of this protein results in thespontaneous assembly of virus-like particles (VLPs), which mimic thestructure of the virus but are incapable of replication. This structureis composed of 180 monomeric subunits of VP1 and are candidate vaccinesto prevent acute gastroenteritis. The VP1 monomer has two domains: ashell (S) domain that forms the inner viral core and a prominentprotruding (P) domain linked by a flexible hinge. The P domain isfurther subdivided into two subdomains P1 and P2, which is the mostsurface exposed region and is thought to contain important cellrecognition and antigenic sites. Homology analysis indicates that themajority of the hypervariable amino acid regions of VP1 are located inthe P2 domain (Allen et al. (2008) PLoS One, Vol. 1:1-9).

Recent epidemiology studies have lead to the hypothesis that Norovirusevolution is epochal with periods of stasis followed by emergence ofnovel epidemic strains, similar to that observed for Influenza virus.Most recent outbreaks appear to be related to emergence of variant virusin the GII.4 genotype at a persistence interval of around two years.There is a need in the art for a vaccine candidate that providesantigenic epitopes that would be cross protective for multipleNorovirus, or other non-enveloped virus strains, which would obviate theneed for construction of vaccines for each contemporary outbreak strain.

SUMMARY OF THE INVENTION

The present invention is based, in part, on the discovery that apolypeptide comprising a composite capsid sequence, which combinesepitopes from a number of circulating viral strains, can be used toproduce a more robust immunological response to multiple viral strains.Such a polypeptide can be used to prepare vaccine formulations that areprotective against several circulating strains of the virus, andtherefore improve strain-to-strain and year-to-year protection.

The present invention provides at least one polypeptide having acomposite amino acid sequence, wherein said composite amino acidsequence is derived from a consensus sequence representing the capsidproteins of two or more circulating strains of a non-enveloped virus,and wherein the at least one polypeptide forms a virus-like particlewhen expressed in a host cell and contains at least 1 different aminoacid as compared to each of the capsid sequences of said two or morecirculating strains. In one embodiment, the virus-like particlecomprising the at least one composite polypeptide has antigenicproperties of the two or more circulating strains of the non-envelopedvirus. In another embodiment, the composite polypeptide or compositevirus-like particle provides an increase in antisera cross-reactivity toone or more circulating strains of the non-enveloped virus as comparedto the antisera cross-reactivity obtained by immunizing with avirus-like particle containing only protein from said one or morecirculating strains.

The virus-like particle may comprise at least one polypeptide having acomposite amino acid sequence derived from a consensus sequencerepresenting capsid proteins of two or more circulating strains of anon-enveloped virus, wherein the non-enveloped virus is selected fromthe group consisting of Calicivirus, Picornavirus, Astrovirus,Adenovirus, Reovirus, Polyomavirus, Papillomavirus, Parvovirus, andHepatitis E virus. In one embodiment, the non-enveloped virus is aCalicivirus. In another embodiment, the Calicivirus is a Norovirus orSapovirus. The Norovirus may be a genogroup I or genogroup II Norovirus.

The consensus sequence may be derived from two or more Norovirus strainsclassified in the same genogroup and genotype. In one embodiment, theconsensus sequence is derived from genogroup II, genotype 4 Norovirusstrains, such as Houston (GenBank Sequence ABY27560), Minerva (alsoknown as Den Haag; GenBank Sequence ABL74395), and Laurens (also knownas Yerseke; GenBank Sequence ABL74391) strains. In another embodiment,the consensus sequence is derived from Norovirus strains from at leasttwo different genotypes within a genogroup. In still another embodiment,the consensus sequence is derived from Norovirus strains from at leasttwo different genogroups.

The present invention also encompasses a virus-like particle comprisingat least one composite polypeptide derived from two or more circulatingCalicivirus strains and a capsid protein from a second non-envelopedvirus, such as Norovirus. The capsid protein may be a VP1 and/or VP2protein from a genogroup I or genogroup II Norovirus. In anotherembodiment, the virus-like particle comprises at least one compositepolypeptide derived from two or more circulating strains of aCalicivirus and a second composite polypeptide derived from two or morecirculating strains of a second Calicivirus. Preferably, the virus-likeparticle has antigenic properties of the two or more circulating strainsof the first Calicivirus and the two or more circulating strains of thesecond Calicivirus.

The present invention also provides an isolated polypeptide or fragmentthereof having a composite amino acid sequence, wherein said compositeamino acid sequence is derived from a consensus sequence representingthe capsid proteins of two or more circulating strains of anon-enveloped virus, and wherein the polypeptide contains at least 1different amino acid as compared to each of the capsid sequences of saidtwo or more circulating strains. The non-enveloped virus may be aCalicivirus, such as a Sapovirus or Norovirus. Alternatively, thenon-enveloped virus may be a Papillomavirus.

The present invention contemplates vaccine formulations comprising oneor more composite polypeptides or composite virus-like particles of theinvention. Each of the composite virus-like particles comprises at leastone polypeptide having a composite amino acid sequence derived from aconsensus sequence representing the capsid proteins from two or morecirculating strains of a non-enveloped virus. The non-enveloped virusmay be a genogroup I or genogroup II Norovirus. In some embodiments, thevaccine formulation further comprises an adjuvant. In other embodiments,the vaccine formulation further comprises a delivery agent. In stillother embodiments, the vaccine formulation further comprises apharmaceutically acceptable carrier. The vaccine formulation may be aliquid formulation or a dry powder formulation.

The invention also provides a method of inducing a protective immunityto a viral infection in a subject comprising administering to thesubject a vaccine formulation disclosed herein. In one embodiment, theviral infection is a Norovirus infection. In another embodiment, thevaccine formulation confers protection from one or more symptoms ofNorovirus infection.

The present invention also contemplates a method of making a compositevirus-like particle. In one embodiment, the method comprises aligningamino acid sequences of capsid proteins from two or more circulatingstrains of a non-enveloped virus; determining a consensus sequence fromsaid aligned amino acid sequences; preparing a composite sequence basedon said consensus sequence that contains at least 1 different amino acidas compared to each of the capsid sequences of said two or morecirculating strains; and expressing said composite sequence in a hostcell, thereby producing a virus-like particle. The non-enveloped virusmay be a Calicivirus, Picornavirus, Astrovirus, Adenovirus, Reovirus,Polyomavirus, Papillomavirus, Parvovirus, and Hepatitis E virus.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1. Amino acid consensus sequence of VP1 proteins from genogroup II,genotype 4 Norovirus (SEQ ID NO: 2). The consensus sequence wasdetermined from an alignment of Houston (GenBank Sequence ABY27560),Minerva (also known as Den Haag and GenBank Sequence ABL74395), andLaurens (also known as Yerseke and GenBank Sequence ABL74391) strains.

FIG. 2. Nucleotide sequence encoding the composite VP1 protein fromgenogroup II, genotype 4 Norovirus (SEQ ID NO: 3). The amino acidsequence encoded by this nucleotide sequence is provided as SEQ ID NO:22.

FIG. 3. SDS-PAGE/Coomassie analysis of sucrose gradient purifiedcomposite VLPs.

FIG. 4. HPLC SEC chromatogram of readings at 220 nm (top) and 280 nm(bottom) of composite expression cell culture supernatant purified bysucrose gradient.

FIG. 5. SDS-PAGE/Silver-stain analysis of composite sequence VLPspurified by column chromatography.

FIG. 6. HPLC SEC chromatogram of readings at 280 nm of composite VLPs.

FIG. 7. Immunization with composite VLP (CVLP) elicits antigen-specificIgG. Groups of 7 mice were immunized (i.p.) with various concentrationsof CVLP (indicated on the X axis) on days 0 and 7. Serum was collectedon day 14 and CVLP-specific IgG was measured by ELISA. Horizontal linesindicate geometric means of each treatment group.

FIG. 8. Immunization with composite VLP/Norwalk VLP (CVLP/NVLP)combination elicits NVLP-specific IgG. Groups of 7 mice were immunized(i.p.) with various concentrations of NVLP alone (purple bars) or incombination with equal amounts of CVLP (black bars) on days 0 and 14.Serum was collected on day 21 and NVLP-specific IgG was measured byELISA. Data is reported as the mean+standard error of the mean (SEM).

FIG. 9. Immunization with composite VLP/Norwalk VLP (CVLP/NVLP)combination elicits CVLP-specific IgG. Groups of 7 mice were immunized(i.p.) with various concentrations of either composite VLP alone (greenbars) or in combination with equal amounts of NVLP (black bars) on days0 and 14. Serum was collected on day 21 and CVLP-specific IgG wasmeasured by ELISA. Data is reported as the mean+standard error of themean (SEM).

FIG. 10. CVLP-specific IgG cross-reacts with other Norovirus isolates.Antibody titers measured 21 days after a single immunization with theeither Composite VLPs or GII.4 2002 VLPs show that Composite VLPselicit˜10 fold higher titers as compared to the GII.4 2002 VLPs.Antibody titers for animals immunized with all GII.4 VLPs show poorcross reactivity to GI.1 VLPs. Data are expressed as geometricmean+standard error of the mean (SEM).

FIG. 11. Rabbits were immunized IM on day 0 and 21 with equal amounts ofNorwalk VLP (NVLP) and composite VLP (CVLP). Serum was collected on day28 and VLP-specific IgG was evaluated. The resulting data was logtransformed and evaluated by linear regression analysis. IgG titers areexpressed as reciprocal dilutions and shown as geometric mean titers.

FIG. 12. Rabbits were immunized IM on day 0 and 21 with equal amounts ofNorwalk VLP (NVLP) and composite VLP (CVLP). Spleens were collected onday 75 and unfractionated cells were stimulated in culture for 5 dayswith either NVLP or CVLP and the amount of thymidine incorporation wasmeasured. The mean and SD are shown for each rabbit in the treatmentgroups indicated on the X axis. Data are expressed as mean+SD.

FIG. 13. Rabbits were immunized IM on day 0 and 21 with equal amounts ofNorwalk VLP (NVLP) and composite VLP (CVLP). Spleens and mesentericlymph nodes (LN) were collected on day 75 and analyzed for the presenceof VLP-specific memory B-cells by ELISPOT. Individual responses areshown for NVLP and CVLP. Data are represented as the number ofVLP-specific IgG secreting cells per million cells present.

FIG. 14. Rabbits were immunized IM on days 0, 14, and 21 with equalamounts of Norwalk VLP (NVLP) and composite VLP (CVLP) as indicated inthe legend. Serum was collected on day 21 and 35 and NVLP-specific IgGand IgA was measured by ELISA. Results are displayed as geometric groupmeans+SEM.

FIG. 15. Rabbits were immunized IM on days 0, 14, and 21 with equalamounts of Norwalk VLP (NVLP) and composite VLP (CVLP) as indicated inthe legend. Serum was collected on day 21 and 35 and CVLP-specific IgGand IgA was measured by ELISA. Results are displayed as geometric groupmeans+SEM.

FIG. 16. Rabbits were immunized IM on days 0, 14, and 21 with equalamounts of Norwalk VLP (NVLP) and composite VLP (CVLP). Spleens werecollected on day 35 and unfractionated cells were stimulated in vitrofor 5 days. Splenocytes were stimulated with various VLPs from the twogenogroups as indicated in the graph legend. Results are displayed asgeometric group means+SD.

FIG. 17. Mice were immunized IP on days 0 and 7 with equal amounts ofNorwalk VLP (NVLP) and composite VLP (CVLP) as indicated on the X axis.Serum was collected on day 14 and analyzed for the presence ofVLP-specific IgG by ELISA. Individual responses are shown and titers areexpressed as reciprocal dilutions. Horizontal bars represent geometricgroup means.

FIG. 18. Mice were immunized IP on days 0 and 7 with equal amounts ofNorwalk VLP (NVLP) and composite VLP (CVLP) as indicated on the X axis.Serum was collected on day 14 and analyzed for the presence ofantibodies capable of inhibiting hemagglutination of human red bloodcells (type O positive). Individual responses are shown and titers areexpressed as reciprocal dilutions. Horizontal bars represent geometricgroup means.

FIG. 19. Serum anti-VLP IgG in rabbits intranasally immunized on days 0and 21 with 50 μg of VLP vaccine formulation (Norwalk VLPs+compositeGII.4 VLPs). Individual responses are shown and expressed in μg/mL fromserum collected on day 35. Bars indicate the geometric group means.

FIG. 20. Amino acid consensus sequence of VP1 proteins from genogroup IINorovirus (SEQ ID NO: 7). The consensus sequence was determined from analignment of GII.1 (Accession Number: AAL13001), GII.2 Snow Mountain(Accession Number: AAB61685), and GII.3 (Accession Number: AAL12998)strains. The “x” indicates positions in which the amino acid differedamong all three strains.

FIG. 21. Amino acid consensus sequence of VP1 proteins from genogroup INorovirus (SEQ ID NO: 12). The consensus sequence was determined from analignment of Norwalk virus (Accession Number: M87661), Southampton(Accession Number: Q04542), and Chiba virus (Accession Number: BAB18267)strains. The “x” indicates positions in which the amino acid differedamong all three strains.

FIG. 22. Amino acid consensus sequence of L1 proteins from HumanPapillomavirus (SEQ ID NO: 17). The consensus sequence was determinedfrom an alignment of HPV-11, HPV-16, and HPV-18 viral strains. The “x”indicates positions in which the amino acid differed among all threestrains.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides vaccine formulations comprising apolypeptide having a composite amino acid sequence, wherein thecomposite amino acid sequence is derived from capsid sequences ofcirculating strains of non-enveloped virus. Virus-like particlesproduced from such polypeptide sequences provide antigenic epitopes forseveral viral strains and can be used to induce an immune response thatis protective against viral infection from multiple strains.Accordingly, the present invention provides a virus-like particlecomprising at least one polypeptide having a composite amino acidsequence. A “composite amino acid sequence” or “composite sequence”, asused herein, is a sequence derived from a consensus sequence of at leasttwo viral protein sequences. In one embodiment, the viral proteinsequences are capsid sequences. A composite amino acid sequence may bederived from a consensus sequence by selecting one of two or more aminoacids at the variable positions in the consensus sequence.

As used herein, a “consensus sequence” is a sequence containing one ormore variable amino acids, and is determined by aligning and comparingthe viral protein sequences of two or more viruses. A consensus sequencemay also be determined by aligning and comparing the nucleotidesequences of two or more viruses. The consensus sequence may bedetermined from protein or nucleotide sequences of two or more, three ormore, four or more, five or more, six or more, seven or more, eight ormore, or nine or more circulating strains of a non-enveloped virus.

The polypeptide having a composite amino acid sequence may contain atleast one different, at least two different, at least three different,at least four different, at least five different, at least sixdifferent, at least seven different, at least eight different, at leastnine different, at least ten different, at least fifteen different, atleast twenty different, at least twenty-five different, at least thirtydifferent, at least thirty-five different, at least forty different, atleast forty-five different, or at least fifty different amino acids ascompared to each of the protein sequences of the two or more circulatingstrains used to determine the consensus sequence. In some embodiments,the polypeptide having a composite amino acid sequence may form avirus-like particle when expressed in a host cell.

In one embodiment of the invention, the virus-like particle (VLP)comprises at least one polypeptide having a composite amino acidsequence, wherein said composite amino acid sequence is derived from aconsensus sequence representing the capsid proteins of two or morecirculating strains of a non-enveloped virus, and wherein the at leastone polypeptide forms a virus-like particle when expressed in a hostcell and contains at least 1 different amino acid as compared to each ofthe capsid sequences of said two or more circulating strains.Preferably, the virus-like particle has antigenic properties of the twoor more, three or more, four or more, five or more, six or more, sevenor more, eight or more, or nine or more circulating strains of anon-enveloped virus. In some embodiments, the virus-like particleprovides an increase in antisera cross-reactivity to one or more, two ormore, three or more, four or more, five or more, six or more, seven ormore, eight or more, or nine or more circulating strains of thenon-enveloped virus as compared to the antisera cross-reactivityobtained by immunizing with a virus-like particle containing onlyprotein from one or more circulating strains. In one embodiment, thevirus-like particle provides at least a two-fold increase in antiseracross-reactivity.

In another embodiment, the virus-like particle comprises at least onepolypeptide having a composite amino acid sequence derived from aconsensus sequence representing the capsid proteins of two or morecirculating strains of a non-enveloped virus, wherein the non-envelopedvirus is selected from the group consisting of Calicivirus,Picornavirus, Astrovirus, Adenovirus, Reovirus, Polyomavirus,Papillomavirus, Parvovirus, and Hepatitis E virus. The invention alsoincludes strains of non-enveloped viruses that have not yet beencharacterized or discovered at the time of filing. In some embodiments,among others, the non-enveloped virus is a Calicivirus. Calicivirusesare divided into four genera: Norovirus and Sapovirus, which causeinfection in humans, and Lagovirus and Vesivirus, which are associatedwith veterinary infections. In preferred embodiments, the Calicivirus isa Sapovirus or Norovirus.

The Norovirus genus is split primarily into two major genogroups (GI andGII). Two other genogroups (GIII and GIV) are proposed, but generallyaccepted. Representative of GIII is the bovine, Jena strain. GIVcontains one virus, Alphatron, at this time. The GI and GII groups maybe further segregated into clusters or genotypes based on geneticclassification (Ando et al. (2000) J. Infectious Diseases, Vol.181(Supp2):S336-S348; Lindell et al. (2005) J. Clin. Microbiol., Vol.43(3): 1086-1092). As used herein, the term genetic clusters is usedinterchangeably with the term genotypes. Within genogroup I, there are 6GI clusters (with prototype virus strain name): GI.1 (Norwalk); GI.2(Southhampton); GI.3 (Desert Shield); GI.4 (Cruise Ship virus/Chiba);GI.5 (318/Musgrove); and GI.6 (Hesse). Within genogroup II, there are 9GII clusters (with prototype virus strain name): GII.1 (Hawaii); 011.2(Snow Mountain/Melksham); 011.3 (Toronto); GII.4 (Bristol/Lordsdale);GII.5 (290/Hillingdon); 011.6 (269/Seacroft); GII.7 (273/Leeds); GII.8(539/Amsterdam); and GII.9 (378). The circulating Norovirus strains areclassified through comparison to prototype strains belonging to thesegenetic clusters. The most prevalent circulating strains belong togenogroup II.

Nucleic acid and protein sequences for a number of Norovirus isolatesare known. Additional representative, non-limiting sequences, includingsequences of ORF1, ORF2, ORF3, and their encoded polypeptides fromNorovirus isolates are listed in the National Center for BiotechnologyInformation (NCBI) database. In one embodiment of the invention, theNorovirus may be a genogroup I or genogroup II Norovirus. Composite andconsensus amino acid sequences may be determined from any of the knownNorovirus strains. See, for example, GenBank entries: Norovirusgenogroup 1 strain Hu/NoV/West Chester/2001/USA, GenBank Accession No.AY502016; Norovirus genogroup 2 strain Hu/NoV/Braddock Heights/1999/USA,GenBank Accession No. AY502015; Norovirus genogroup 2 strainHu/NoV/Fayette/1999/USA, GenBank Accession No. AY502014; Norovirusgenogroup 2 strain Hu/NoV/Fairfield/1999/USA, GenBank Accession No.AY502013; Norovirus genogroup 2 strain Hu/NoV/Sandusky/1999/USA, GenBankAccession No. AY502012; Norovirus genogroup 2 strainHu/NoV/Canton/1999/USA, GenBank Accession No. AY502011; Norovirusgenogroup 2 strain Hu/NoV/Tiffin/1999/USA, GenBank Accession No.AY502010; Norovirus genogroup 2 strain Hu/NoV/CS-E1/2002/USA, GenBankAccession No. AY50200; Norovirus genogroup 1 strainHu/NoV/Wisconsin/2001/USA, GenBank Accession No. AY502008; Norovirusgenogroup 1 strain Hu/NoV/CS-841/2001/USA, GenBank Accession No.AY502007; Norovirus genogroup 2 strain Hu/NoV/Hiram/2000/USA, GenBankAccession No. AY502006; Norovirus genogroup 2 strainHu/NoV/Tontogany/1999/USA, GenBank Accession No. AY502005; Norwalkvirus, complete genome, GenBank Accession No. NC.sub.--001959; NorovirusHu/GI/Otofuke/1979/JP genomic RNA, complete genome, GenBank AccessionNo. AB 187514; Norovirus Hu/Hokkaido/133/2003/JP, GenBank Accession No.AB212306; Norovirus Sydney 2212, GenBank Accession No. AY588132; Norwalkvirus strain SN2000JA, GenBank Accession No. AB190457; Lordsdale viruscomplete genome, GenBank Accession No. X86557; Norwalk-like virusgenomic RNA, Gifu'96, GenBank Accession No. AB045603; Norwalk virusstrain Vietnam 026, complete genome, GenBank Accession No. AF504671;Norovirus Hu/GII.4/2004/N/L, GenBank Accession No. AY883096; NorovirusHu/GII/Hokushin/03/JP, GenBank Accession No. AB 195227; NorovirusHu/GII/Kamo/03/JP, GenBank Accession No. AB195228; NorovirusHu/GII/Sinsiro/97/JP, GenBank Accession No. AB 195226; NorovirusHu/GII/Ina/02/JP, GenBank Accession No. AB195225; NorovirusHu/NLV/GII/Neustrelitz260/2000/DE, GenBank Accession No. AY772730;Norovirus Hu/NLV/Dresden174/pUS-NorII/1997/GE, GenBank Accession No.AY741811; Norovirus Hu/NLV/Oxford/B2S16/2002/UK, GenBank Accession No.AY587989; Norovirus Hu/NLV/Oxford/B4S7/2002/UK, GenBank Accession No.AY587987; Norovirus Hu/NLV/Witney/B7S2/2003/UK, GenBank Accession No.AY588030; Norovirus Hu/NLV/Banbury/B9S23/2003/UK, GenBank Accession No.AY588029; Norovirus Hu/NLV/ChippingNorton/2003/UK, GenBank Accession No.AY588028; Norovirus Hu/NLV/Didcot/B9S2/2003/UK, GenBank Accession No.AY588027; Norovirus Hu/NLV/Oxford/B8S5/2002/UK, GenBank Accession No.AY588026; Norovirus Hu/NLV/Oxford/B6S4/2003/UK, GenBank Accession No.AY588025; Norovirus Hu/NLV/Oxford/B6S5/2003/UK, GenBank Accession No.AY588024; Norovirus Hu/NLV/Oxford/B5S23/2003/UK, GenBank Accession No.AY588023; Norovirus Hu/NLV/Oxford/B6S2/2003/UK, GenBank Accession No.AY588022; Norovirus Hu/NLV/Oxford/B6S6/2003/UK, GenBank Accession No.AY588021; Norwalk-like virus isolate Bo/Thirsk10/00/UK, GenBankAccession No. AY126468; Norwalk-like virus isolate Bo/Penrith55/00/UK,GenBank Accession No. AY126476; Norwalk-like virus isolateBo/Aberystwyth24/00/UK, GenBank Accession No. AY126475; Norwalk-likevirus isolate Bo/Dumfries/94/UK, GenBank Accession No. AY126474;Norovirus NLV/IF2036/2003/Iraq, GenBank Accession No. AY675555;Norovirus NLV/IF1998/2003/Iraq, GenBank Accession No. AY675554;Norovirus NLV/BUDS/2002/USA, GenBank Accession No. AY660568; NorovirusNLV/Paris Island/2003/USA, GenBank Accession No. AY652979; Snow Mountainvirus, complete genome, GenBank Accession No. AY134748; Norwalk-likevirus NLV/Fort Lauderdale/560/1998/US, GenBank Accession No. AF414426;HuNorovirus/hiroshima/1999/JP (9912-02F), GenBank Accession No.AB044366; Norwalk-like virus strain 11MSU-MW, GenBank Accession No.AY274820; Norwalk-like virus strain B-1SVD, GenBank Accession No.AY274819; Norovirus genogroup 2 strain Hu/NoV/Farmington Hills/2002/USA,GenBank Accession No. AY502023; Norovirus genogroup 2 strainHu/NoV/CS-G4/2002/USA, GenBank Accession No. AY502022; Norovirusgenogroup 2 strain Hu/NoV/CS-G2/2002/USA, GenBank Accession No.AY502021; Norovirus genogroup 2 strain Hu/NoV/CS-G12002/USA, GenBankAccession No. AY502020; Norovirus genogroup 2 strainHu/NoV/Anchorage/2002/USA, GenBank Accession No. AY502019; Norovirusgenogroup 2 strain Hu/NoV/CS-D1/2002/CAN, GenBank Accession No.AY502018; Norovirus genogroup 2 strain HuNoV/Germanton/2002/USA, GenBankAccession No. AY502017; Human calicivirus NLV/GII/Langen1061/2002/DE,complete genome, GenBank Accession No. AY485642; Murine norovirus 1polyprotein, GenBank Accession No. AY228235; Norwalk virus, GenBankAccession No. AB067536; Human calicivirus NLV/Mex7076/1999, GenBankAccession No. AF542090; Human calicivirus NLV/Oberhausen 455/01/DE,GenBank Accession No. AF539440; Human calicivirus NLV/Herzberg385/01/DE, GenBank Accession No. AF539439; Human calicivirusNLV/Boxer/2001/US, GenBank Accession No. AF538679; Norwalk-like virusgenomic RNA, complete genome, GenBank Accession No. AB081723;Norwalk-like virus genomic RNA, complete genome, isolate:Saitama U201,GenBank Accession No. AB039782; Norwalk-like virus genomic RNA, completegenome, isolate:Saitama U18, GenBank Accession No. AB039781;Norwalk-like virus genomic RNA, complete genome, isolate:Saitama U25,GenBank Accession No. AB039780; Norwalk virus strain:U25GII, GenBankAccession No. AB067543; Norwalk virus strain:U201 GII, GenBank AccessionNo. AB067542; Norwalk-like viruses strain 416/97003156/1996/LA, GenBankAccession No. AF080559; Norwalk-like viruses strain408/97003012/1996/FL, GenBank Accession No. AF080558; Norwalk-like virusNLV/Burwash Landing/331/1995/US, GenBank Accession No. AF414425;Norwalk-like virus NLV/Miami Beach/326/1995/US, GenBank Accession No.AF414424; Norwalk-like virus NLV/White River/290/1994/US, GenBankAccession No. AF414423; Norwalk-like virus NLV/New Orleans/306/1994/US,GenBank Accession No. AF414422; Norwalk-like virus NLV/PortCanaveral/301/1994/US, GenBank Accession No. AF414421; Norwalk-likevirus NLV/Honolulu/314/1994/US, GenBank Accession No. AF414420;Norwalk-like virus NLV/Richmond/283/1994/US, GenBank Accession No.AF414419; Norwalk-like virus NLV/Westover/302/1994/US, GenBank AccessionNo. AF414418; Norwalk-like virus NLV/UK3-17/12700/1992/GB, GenBankAccession No. AF414417; Norwalk-like virus NLV/Miami/81/1986/US, GenBankAccession No. AF414416; Snow Mountain strain, GenBank Accession No.U70059; Desert Shield virus DSV395, GenBank Accession No. U04469;Norwalk virus, complete genome, GenBank Accession No. AF093797; Hawaiicalicivirus, GenBank Accession No. U07611; Southampton virus, GenBankAccession No. L07418; Norwalk virus (SRSV-KY-89/89/J), GenBank AccessionNo. L23828; Norwalk virus (SRSV-SMA/76/US), GenBank Accession No.L23831; Camberwell virus, GenBank Accession No. U46500; Humancalicivirus strain Melksham, GenBank Accession No. X81879; Humancalicivirus strain MX, GenBank Accession No. U22498; Minireovirus TV24,GenBank Accession No. U02030; and Norwalk-like virusNLV/Gwynedd/273/1994/US, GenBank Accession No. AF414409; sequences ofall of which (as entered by the date of filing of this application) areherein incorporated by reference. Additional Norovirus sequences aredisclosed in the following patent publications: WO 2005/030806, WO2000/79280, JP2002020399, US2003129588, U.S. Pat. No. 6,572,862, WO1994/05700, and WO 05/032457, all of which are herein incorporated byreference in their entireties. See also Green et al. (2000) J. Infect.Dis., Vol. 181(Suppl. 2):S322-330; Wang et al. (1994) J. Virol., Vol.68:5982-5990; Chen et al. (2004) J. Virol., Vol. 78: 6469-6479;Chakravarty et al. (2005) J. Virol., Vol. 79: 554-568; Hansman et al.(2006) J. Gen. Virol., Vol. 87:909-919; Bull et al. (2006) J. Clin.Micro., Vol. 44(2):327-333; Siebenga, et al. (2007) J. Virol., Vol.81(18):9932-9941, and Fankhauser et al. (1998) J. Infect. Dis., Vol.178:1571-1578; for sequence comparisons and a discussion of geneticdiversity and phylogenetic analysis of Noroviruses.

Nucleic acid and protein sequences for a number of Sapovirus isolatesare also known. Representative Sapovirus sequences, including sequencesof ORF1 and ORF2, and their encoded polypeptides from Sapovirus isolatesare listed in the National Center for Biotechnology Information (NCBI)database. See, for example, GenBank entries: Sapovirus Mc10, GenBankAccession No. NC.sub.--010624; Sapporo virus, GenBank Accession No.U65427; Sapovirus Mc10, GenBank Accession No. AY237420; SapovirusSaKaeo-15/Thailand, GenBank Accession No. AY646855; Sapporo virus,GenBank Accession No. NC.sub.--006269; Sapovirus C12, GenBank AccessionNo. NC.sub.--006554; Sapovirus C12, GenBank Accession No. AY603425;Sapovirus Hu/Dresden/pJG-Sap01/DE, GenBank Accession No. AY694184; Humancalicivirus SLV/cruise ship/2000/USA, GenBank Accession No. AY289804;Human calicivirus SLV/Arg39, GenBank Accession No. AY289803; Porcineenteric calicivirus strain LL14, GenBank Accession No. AY425671; Porcineenteric calicivirus, GenBank Accession No. NC.sub.--000940; Humancalicivirus strain Mc37, GenBank Accession No. AY237415; Mink entericcalicivirus strain Canada 151A, GenBank Accession No. AY144337; Humancalicivirus SLV/Hou7-1181, GenBank Accession No. AF435814; Humancalicivirus SLV/Mex14917/2000, GenBank Accession No. AF435813; Humancalicivirus SLV/Mex340/1990, GenBank Accession No. AF435812; Porcineenteric calicivirus, GenBank Accession No. AF182760; Sapporovirus-London/29845, GenBank Accession No. U95645; Sapporovirus-Manchester, GenBank Accession No. X86560; Sapporovirus-Houston/86, GenBank Accession No. U95643; Sapporovirus-Houston/90, GenBank Accession No. U95644; and Human calicivirusstrain HuCV/Potsdam/2000/DEU, GenBank Accession No. AF294739; sequencesof all of which (as entered by the date of filing of this application)are herein incorporated by reference. See also Schuffenecker et al.(2001) Arch Virol., Vol. 146(11):2115-2132; Zintz et al. (2005) Infect.Genet. Evol., Vol. 5:281-290; Farkas et al. (2004) Arch. Virol., Vol.149:1309-1323; for sequence comparisons and a discussion of geneticdiversity and phylogenetic analysis of Sapoviruses.

The composite and consensus amino acid sequences may be derived fromcapsid sequences of at least two Norovirus genogroup I or genogroup IIstrains. In one embodiment, the VLP comprises a polypeptide having acomposite sequence derived from a consensus sequence of the capsidproteins from two or more genogroup II, genotype 4 Norovirus strains.Non-limiting examples of genogroup II, genotype 4 Norovirus strainsinclude Houston strain, Minerva strain, Laurens strain, Bristol strain,Lordsdale strain, Farmington Hills strain, Hunter strain, Carlow strain,and the US95/96-US, 2006a, and 2006b strains.

In another embodiment of the invention, the virus-like particle iscomprised of at least one composite polypeptide wherein the sequence ofthe composite polypeptide is derived from the VP1 sequences of Houston,Minerva, and Laurens. In another embodiment, the composite sequencecomprises or consists of SEQ ID NO: 1 or SEQ ID NO: 22. In still anotherembodiment, composite sequences based on Houston, Minerva, and Laurensmay be derived from the consensus sequence defined by SEQ ID NO: 2.

In some embodiments, the consensus sequence may be determined fromNorovirus strains from at least two different genotypes or at least twodifferent genogroups. In one embodiment of the present invention thevirus-like particle is comprised of at least one polypeptide having acomposite amino acid sequence, wherein the composite amino acid sequenceis derived from a consensus sequence of capsid proteins of Norovirusstrains from at least two different genotypes within a genogroup. By wayof example, the consensus sequence may be derived from the capsidsequences of genogroup II, genotype 2 and genogroup II, genotype 4Norovirus strains. In another embodiment, the consensus sequence may bederived from the capsid sequences of three or more genotypes within agenogroup.

In other embodiments, the consensus sequence may be determined fromNorovirus strains from at least two different genogroups. One suchembodiment, among others, would be a VLP comprising a polypeptide havinga composite amino acid sequence, wherein said composite amino acidsequence is derived from a consensus sequence of capsid proteins ofgenogroup I, genotype 1 and genogroup II, genotype 4 Norovirus strains.

The present invention also provides a virus-like particle (VLP)comprising a composite polypeptide derived from a consensus sequence ofcapsid proteins from two or more circulating strains of Norovirus and acapsid protein from a second Norovirus. The second Norovirus may be agenogroup I or genogroup II Norovirus. The capsid protein from thesecond Norovirus can be the major capsid protein, VP1, which is encodedby ORF 2, or the minor capsid protein, VP2, which is encoded by ORF 3,or combinations of VP1 and VP2. In one embodiment, the capsid proteinfrom the second Norovirus is a VP1 protein from a genogroup I Norovirus.

In another embodiment, the invention provides a VLP comprising acomposite polypeptide derived from a consensus sequence representing thecapsid proteins of two or more circulating strains of Calicivirus and asecond polypeptide having a second composite amino acid sequence,wherein said second composite amino acid sequence is derived from aconsensus sequence representing the capsid proteins of two or morecirculating strains of a second Calicivirus. Preferably, the virus-likeparticle has antigenic properties of the two or more circulating strainsof the first Calicivirus and the two or more circulating strains of thesecond Calicivirus.

The second polypeptide contains at least one different, at least threedifferent, at least five different, at least ten different, at leastfifteen different, at least twenty different, at least twenty-fivedifferent, at least thirty different, at least thirty-five different, atleast forty different, at least forty-five different, or at least fiftydifferent amino acids as compared to each of the capsid sequences ofsaid two or more circulating strains of the second Calicivirus. In someembodiments, the second polypeptide forms a virus-like particle whenexpressed in a host cell. In another embodiment, the second Calicivirusis a Norovirus. In another embodiment, the Norovirus is a genogroup INorovirus. The genogroup I Norovirus may be any of the genogroup Istrains disclosed herein. In one embodiment, the genogroup I Norovirusis selected from the group consisting of Norwalk virus, Southamptonvirus, Hesse virus, and Chiba virus.

The present invention also encompasses isolated polypeptides orfragments thereof having the composite amino acid sequences defined herein, as well as nucleic acids or vectors encoding the same. In oneembodiment, the isolated polypeptide or fragment thereof has a compositeamino acid sequence, wherein said composite amino acid sequence isderived from a consensus sequence representing the capsid proteins oftwo or more circulating strains of a non-enveloped virus, and whereinthe polypeptide contains at least 1 different amino acid as compared toeach of the capsid sequences of said two or more circulating strains. Inanother embodiment, the composite sequence contains at least 3 differentamino acids compared to the capsid sequence of one or more circulatingstrains of the non-enveloped virus. In another embodiment, the compositesequence contains 5-50 different amino acids compared to the capsidsequence of one or more circulating strains of the non-enveloped virus.In still another embodiment, the consensus sequence is SEQ ID NO: 2.

The composite polypeptide may have a sequence derived from two or morecirculating strains of any non-enveloped virus disclosed herein. In oneembodiment, the non-enveloped virus is a Calicivirus. In anotherembodiment, the Calicivirus is a Norovirus or Sapovirus. In anotherembodiment, the Norovirus is a genogroup I or genogroup II Norovirus, orcombinations thereof. In yet another embodiment, the isolatedpolypeptide comprises the amino acid sequence of SEQ ID NO: 1 or SEQ IDNO: 22.

In one embodiment, the present invention provides an isolated nucleicacid encoding the polypeptide having a composite amino acid sequence,wherein said composite amino acid sequence is derived from a consensussequence representing the capsid proteins of two or more circulatingstrains of a non-enveloped virus, and wherein the polypeptide containsat least 1 different amino acid as compared to each of the capsidsequences of said two or more circulating strains. In anotherembodiment, the nucleic acid has the sequence of SEQ ID NO: 3. Inanother embodiment, the invention provides a vector comprising anisolated nucleic acid encoding a composite polypeptide. In yet anotherembodiment, the invention provides a host cell comprising a vectorencoding a composite polypeptide.

The antigenic molecules of the present invention (e.g. VLPs,polypeptides, and fragments thereof) can be prepared by isolation andpurification from the organisms in which they occur naturally, or theymay be prepared by recombinant techniques. Once coding sequences for thedesired particle-forming polypeptides have been isolated or synthesized,they can be cloned into any suitable vector or replicon for expression.Numerous cloning vectors are known to those of skill in the art, and theselection of an appropriate cloning vector is within the skill of anordinary artisan. The vector is then used to transform an appropriatehost cell. Suitable recombinant expression systems include, but are notlimited to, bacterial (e.g. E. coli, Bacillus subtilis, andStreptococcus), baculovirus/insect, vaccinia, Semliki Forest virus(SFV), Alphaviruses (such as, Sindbis, Venezuelan Equine Encephalitis(VEE)), mammalian (e.g. Chinese hamster ovary (CHO) cells, HEK-293cells, HeLa cells, baby hamster kidney (BHK) cells, mouse myeloma(SB20), and monkey kidney cells (COS)), yeast (e.g. S. cerevisiae, S.pombe, Pichia pastori and other Pichia expression systems), plant, andXenopus expression systems, as well as others known in the art.Particularly preferred expression systems are mammalian cell lines,bacteria, insect cells, and yeast expression systems.

Each of the aforementioned antigens (e.g. VLPs, polypeptides, orfragments thereof) is preferably used in the substantially pure state.Depending on the expression system and host selected, VLPs are producedby growing host cells transformed by an expression vector underconditions whereby the particle-forming polypeptide is expressed andVLPs can be formed. The selection of the appropriate growth conditionsis within the skill of the art.

Preferably the VLP antigens are prepared from insect cells such as Sf9,High Five, TniPro, Aedes aegypti, Autographa californica, Bombyx mori,Drosophila melanogaster, Spodoptera frugiperda, and Trichoplusia ni. Theprocedures for producing VLPs in insect cell culture is well known inthe art (see, for example, U.S. Pat. No. 6,942,865, which isincorporated herein by reference in its entirety). Briefly, therecombinant baculoviruses carrying the composite capsid sequence areconstructed from the sythetic cDNAs. The recombinant baculovirus arethen used to infect insect cell cultures (e.g. Sf9, High Five and TniProcells) and composite VLPs can be isolated from the cell culture. A“composite VLP” is a VLP comprising at least one polypeptide having acomposite amino acid sequence derived from a consensus sequencerepresenting the capsid proteins of two or more circulating strains of anon-enveloped virus.

If the VLPs are formed intracellularly, the cells are then disrupted,using chemical, physical or mechanical means, which lyse the cells yetkeep the VLPs substantially intact. Such methods are known to those ofskill in the art and are described in, e.g., Protein PurificationApplications: A Practical Approach, (E. L. V. Harris and S. Angal, Eds.,1990).

The particles are then isolated (or substantially purified) usingmethods that preserve the integrity thereof, such as, by densitygradient centrifugation, e.g., sucrose gradients, PEG-precipitation,pelleting, and the like (see, e.g., Kirnbauer et al. J. Virol. (1993)67:6929-6936), as well as standard purification techniques including,e.g., ion exchange and gel filtration chromatography.

General texts which describe molecular biological techniques, which areapplicable to the present invention, such as cloning, mutation, and thelike, include Berger and Kimmel, Guide to Molecular Cloning Techniques,Methods in Enzymology volume 152 Academic Press, Inc., San Diego, Calif.(Berger); Sambrook et al., Molecular Cloning—A Laboratory Manual (3rdEd.), Vol. 1-3, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.,2000 (“Sambrook”) and Current Protocols in Molecular Biology, F. M.Ausubel et al., eds., Current Protocols, a joint venture between GreenePublishing Associates, Inc. and John Wiley & Sons, Inc., (“Ausubel”).These texts describe mutagenesis, the use of vectors, promoters and manyother relevant topics related to, e.g., the cloning and expression ofcapsid proteins of non-enveloped viruses, such as Calicivirus.

In some embodiments, the antigenic molecules of the present invention(e.g. VLPs, polypeptides, and fragments thereof) are produced in vivo byadministration of a vector comprising an isolated nucleic acid encodinga composite polypeptide. Suitable vectors include, but are not limitedto, viral vectors, such as Vesicular Stomatitis Virus (VSV) vector,Equine Encephalitis Virus (EEV) vector, Poxvirus vector, Adenovirusvector, Adeno-Associated Virus (AAV), retrovirus vector, and expressionplasmids, such as pFastBacl, pWINEO, pSV2CAT, pOG44, pXT1, pSG, pSVK3,pBPV, pMSG, and pSVL. Other suitable vectors will be readily apparent tothe skilled artisan.

The present invention also encompasses a vaccine formulation comprisingthe VLPs, polypeptides, or nucleic acids described herein. In oneembodiment, the vaccine formulation comprises a composite VLP and asecond virus-like particle, wherein said second virus-like particlecomprises a capsid protein from a Norovirus. The second VLP may comprisea native capsid protein from a genogroup I or genogroup II Norovirus.The second VLP may comprise a full length Norovirus capsid protein suchas VP1 and/or VP2 protein or certain VP1 or VP2 derivatives.Alternatively, the second VLP comprises a truncated capsid protein, suchas a truncated VP1 protein. The truncation may be an N- or C-terminaltruncation. Truncated capsid proteins are suitably functional capsidprotein derivatives. Functional capsid protein derivatives are capableof raising an immune response in the same way as the immune response israised by a VLP consisting of the full length capsid protein. Vaccineformulations comprising mixtures of VLPs are described in WO2008/042789, which is herein incorporated by reference in its entirety.Purely by way of example the vaccine formulation can contain VLPs fromone or more strains of Norovirus genogroup I together with VLPscomprising a composite protein from one or more strains of Norovirusgenogroup II. Preferably, the Norovirus VLP mixture is composed of thestrains of Norwalk and genogroup II, genotype 4 Noroviruses. In anotherembodiment, the vaccine formulation comprises a composite VLP and aNorwalk VLP, wherein the composite VLP comprises a polypeptide having anamino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 22. In still anotherembodiment, the vaccine formulation comprises a first composite VLP anda second composite VLP, wherein said first and second composite VLPscomprise at least one polypeptide derived from different consensussequences. For instance, a first composite VLP comprises a compositeprotein from one or more strains of Norovirus genogroup I and a secondcomposite VLP comprises a composite protein from one or more strains ofNorovirus genogroup II. In one embodiment, the first composite VLPcomprises a composite protein from one or more strains of Norovirusgenogroup I, genotype 1 (GI.1) and a second composite VLP comprises acomposite protein from one or more strains of Norovirus genogroup II,genotype 4 (GII.4).

In some embodiments, the vaccine formulation further comprises anadjuvant. Most adjuvants contain a substance designed to protect theantigen from rapid catabolism, such as aluminum hydroxide or mineraloil, and a stimulator of immune responses, such as Bordatella pertussisor Mycobacterium tuberculosis derived proteins. Suitable adjuvants arecommercially available as, for example, Freund's Incomplete Adjuvant andComplete Adjuvant (Pifco Laboratories, Detroit, Mich.); Merck Adjuvant65 (Merck and Company, Inc., Rahway, N.J.); mineral salts, includingaluminum salts such as aluminum hydroxide gel (alum) or aluminumphosphate and salts of calcium, iron or zinc; an insoluble suspension ofacylated tyrosine acylated sugars; cationically or anionicallyderivatized polysaccharides; polyphosphazenes; biodegradablemicrospheres; and Quil A.

Suitable adjuvants also include, but are not limited to, toll-likereceptor (TLR) agonists, monophosphoryl lipid A (MPL), synthetic lipidA, lipid A mimetics or analogs, aluminum salts, cytokines, saponins,muramyl dipeptide (MDP) derivatives, CpG oligos, lipopolysaccharide(LPS) of gram-negative bacteria, polyphosphazenes, emulsions, virosomes,cochleates, poly(lactide-co-glycolides) (PLG) microparticles, poloxamerparticles, microparticles, liposomes, oil-in-water emulsion, MF59, andsqualene. In some embodiments, the adjuvants are bacterially-derivedexotoxins. In other embodiments, adjuvants which stimulate a Th1 typeresponse, such as 3DMPL or QS21, may be used. In certain embodiments,the adjuvant is a combination of MPL and aluminum hydroxide.

In some embodiments, the adjuvant is monophosphoryl lipid A (MPL). MPLis a non-toxic derivative of lipid A from Salmonella, is a potent TLR-4agonist that has been developed as a vaccine adjuvant (Evans et al.(2003) Expert Rev Vaccines, Vol. 2: 219-229). In pre-clinical murinestudies intranasal MPL has been shown to enhance secretory, as well assystemic, humoral responses (Baldridge et al. (2000) Vaccine, Vol. 18:2416-2425; Yang et al. (2002) Infect Immun., Vol. 70: 3557-3565). It hasalso been proven to be safe and effective as a vaccine adjuvant inclinical studies of greater than 120,000 patients (Baldrick et al.(2002) Regul Toxicol Pharmacol, Vol. 35: 398-413). MPL stimulates theinduction of innate immunity through the TLR-4 receptor and is thuscapable of eliciting nonspecific immune responses against a wide rangeof infectious pathogens, including both gram negative and gram positivebacteria, viruses, and parasites (Persing et al. (2002) TrendsMicrobiol, Vol. 10: S32-37). Inclusion of MPL in intranasal formulationsshould provide rapid induction of innate responses, elicitingnonspecific immune responses from viral challenge while enhancing thespecific responses generated by the antigenic components of the vaccine.In some embodiments, MPL can be combined with one or more additionaladjuvants. For instance, MPL can be combined with aluminum hydroxide tocreate a suitable adjuvant for intramuscular administration of a vaccineformulation.

In other embodiments, the adjuvant is a naturally occurring oil, such assqualene. Squalene is a triterpenoid hydrocarbon oil (C₃₀H₅₀) producedby plants and is present in many foods. Squalene is also producedabundantly by human beings, for whom it serves as a precursor ofcholesterol and steroid hormones. It is synthesized in the liver and theskin, transported in the blood by very-low-density lipoproteins (VLDL)and low-density lipoproteins (LDL), and secreted in large amounts bysebaceous glands.

Since it is a natural component of the human body and is biodegradable,squalene has been used as a component of vaccine adjuvants. One of thesesqualene adjuvants is MF59, an oil-in-water emulsion developed byChiron. MF59 has been shown in various preclinical and clinical studiesto significantly enhance the immune response to a wide variety ofvaccine antigens. MF59 is a part of an influenza subunit vaccine, whichhas been licensed in various European countries since 1997. More than 20million doses of this vaccine have been given, and it has been shown tohave an excellent safety profile. The safety of vaccines with the MF59adjuvant has also been shown by various investigational clinical studiesusing recombinant antigens from hepatitis B virus, hepatitis C virus,cytomegalovirus, herpes simplex virus, human immunodeficiency virus,uropathogenic Escherichia coli, etc., in various age groups, including1- to 3-day-old newborns.

The term “effective adjuvant amount” or “effective amount of adjuvant”will be well understood by those skilled in the art, and includes anamount of one or more adjuvants which is capable of stimulating theimmune response to an administered antigen, i.e., an amount thatincreases the immune response of an administered antigen composition, asmeasured in terms of the IgA levels in the nasal washings, serum IgG orIgM levels, or B and T-Cell proliferation. Suitably effective increasesin immunoglobulin levels include by more than 5%, preferably by morethan 25%, and in particular by more than 50%, as compared to the sameantigen composition without any adjuvant.

In another embodiment of the invention, the vaccine formulation mayfurther comprise a delivery agent, which functions to enhance antigenuptake based upon, but not restricted to, increased fluid viscosity dueto the single or combined effect of partial dehydration of hostmucopolysaccharides, the physical properties of the delivery agent, orthrough ionic interactions between the delivery agent and host tissuesat the site of exposure, which provides a depot effect. Alternatively,the delivery agent can increase antigen retention time at the site ofdelivery (e.g., delay expulsion of the antigen). Such a delivery agentmay be a bioadhesive agent. In some embodiments, the bioadhesive may bea mucoadhesive agent selected from the group consisting ofglycosaminoglycans (e.g., chondroitin sulfate, dermatan sulfatechondroitin, keratan sulfate, heparin, heparan sulfate, hyaluronan),carbohydrate polymers (e.g., pectin, alginate, glycogen, amylase,amylopectin, cellulose, chitin, stachyose, unulin, dextrin, dextran),cross-linked derivatives of poly(acrylic acid), polyvinyl alcohol,polyvinyl pyrollidone, polysaccharides (including mucin, othermucopolysaccharides, and GelSite®, a natural acidic polysaccharideextracted from the aloe plant), polyions, cellulose derivatives (e.g.,hydroxypropyl methylcellulose, carboxymethylcellulose), proteins (e.g.lectins, fimbrial proteins), and deoxyribonucleic acid. In oneembodiment, the vaccine formulations comprise a polysaccharide such aschitosan, chitosan salt, chitosan base, or a natural polysaccharide(e.g. GelSite®).

Chitosan, a positively charged linear polysaccharide derived from chitinin the shells of crustaceans, is a bioadhesive for epithelial cells andtheir overlaying mucus layer. Formulation of antigens with chitosanincreases their contact time with the nasal membrane, thus increasinguptake by virtue of a depot effect (Illum et al. (2001) Adv Drug DelivRev, Vol. 51: 81-96; Illum et al. (2003) J Control Release, Vol. 87:187-198; Davis et al. (1999) Pharm Sci Technol Today, Vol. 2: 450-456;Bacon et al. (2000) Infect Immun., Vol. 68: 5764-5770; van der Lubben etal. (2001) Adv Drug Deliv Rev, Vol. 52: 139-144; van der Lubben et al.(2001) Eur J Pharm Sci, Vol. 14: 201-207; Lim et al. (2001) AAPS PharmSci Tech, Vol. 2: 20). Chitosan has been tested as a nasal deliverysystem for several vaccines, including influenza, pertussis anddiphtheria, in both animal models and humans (Ilium et al. (2001) AdvDrug Deliv Rev, Vol. 51: 81-96; Illum et al. (2003) J Control Release,Vol. 87: 187-198; Bacon et al. (2000) Infect Immun., Vol. 68: 5764-5770;Jabbal-Gill et al. (1998) Vaccine, Vol. 16: 2039-2046; Mills et al.(2003) A Infect Immun, Vol. 71: 726-732; McNeela et al. (2004) Vaccine,Vol. 22: 909-914). In these trials, chitosan was shown to enhancesystemic immune responses to levels equivalent to parenteralvaccination. In addition, significant antigen-specific IgA levels werealso measured in mucosal secretions. Thus, chitosan can greatly enhancea nasal vaccine's effectiveness. Moreover, due to its physicalcharacteristics, chitosan is particularly well suited to intranasalvaccines formulated as powders (van der Lubben et al. (2001) Eur J PharmSci, Vol. 14: 201-207; Mikszta et al. (2005) J Infect Dis, Vol. 191:278-288; Huang et al. (2004) Vaccine, Vol. 23: 794-801).

In another embodiment of the invention, the vaccine formulation mayfurther comprise a pharmaceutically acceptable carrier. Apharmaceutically acceptable carrier, including any suitable diluent orexcipient, includes any pharmaceutical agent that does not itself inducethe production of an immune response harmful to the subject receivingthe vaccine formulation, and which may be administered without unduetoxicity. As used herein, the term “pharmaceutically acceptable” meansbeing approved by a regulatory agency of the Federal or a stategovernment or listed in the U.S. Pharmacopia, European Pharmacopia orother generally recognized pharmacopia for use in mammals, and moreparticularly in humans. Pharmaceutically acceptable carriers include,but are not limited to, saline, buffered saline, dextrose, water,glycerol, sterile isotonic aqueous buffer, and combinations thereof. Athorough discussion of pharmaceutically acceptable carriers, diluents,and other excipients is presented in Remington's Pharmaceutical Sciences(Mack Pub. Co. N.J. current edition). The formulation should suit themode of administration. In a preferred embodiment, the formulation issuitable for administration to humans, preferably the formulation issterile, non-particulate and/or non-pyrogenic. The vaccine formulation,if desired, can also contain minor amounts of wetting or emulsifyingagents, or pH buffering agents.

In some embodiments of the present invention, among others, vaccineformulations comprise chitosan, a chitosan salt, or a chitosan base. Themolecular weight of the chitosan may be between 10 kDa and 800 kDa,preferably between 100 kDa and 700 kDa and more preferably between 200kDa and 600 kDa. The concentration of chitosan in the composition willtypically be up to about 80% (w/w), for example, 5%, 10%, 30%, 50%, 70%or 80%. The chitosan is one which is preferably at least 75%deacetylated, for example 80-90%, more preferably 82-88% deacetylated,particular examples being 83%, 84%, 85%, 86% and 87% deacetylation.

The compositions of the invention can be formulated for administrationas vaccines or antigenic formulations. As used herein, the term“vaccine” refers to a formulation which contains VLPs or other antigensof the present invention as described above, which is in a form that iscapable of being administered to a vertebrate and which induces aprotective immune response sufficient to induce immunity to preventand/or ameliorate an infection and/or to reduce at least one symptom ofan infection and/or to enhance the efficacy of another dose of VLPs orantigen. As used herein, the term “antigenic formulation” or “antigeniccomposition” refers to a preparation which, when administered to avertebrate, e.g. a mammal, will induce an immune response. As usedherein, the term “immune response” refers to both the humoral immuneresponse and the cell-mediated immune response. The humoral immuneresponse involves the stimulation of the production of antibodies by Blymphocytes that, for example, neutralize infectious agents, blockinfectious agents from entering cells, block replication of saidinfectious agents, and/or protect host cells from infection anddestruction. The cell-mediated immune response refers to an immuneresponse that is mediated by T-lymphocytes and/or other cells, such asmacrophages, against an infectious agent, exhibited by a vertebrate(e.g., a human), that prevents or ameliorates infection or reduces atleast one symptom thereof. In particular, “protective immunity” or“protective immune response” refers to immunity or eliciting an immuneresponse against an infectious agent, which is exhibited by a vertebrate(e.g., a human), that prevents or ameliorates an infection or reduces atleast one symptom thereof. Specifically, induction of a protectiveimmune response from administration of the vaccine is evident byelimination or reduction of the presence of one or more symptoms ofgastroenteritis or a reduction in the duration or severity of suchsymptoms. Clinical symptoms of gastroenteritis from Norovirus includenausea, diarrhea, loose stool, vomiting, fever, and general malaise. Aprotective immune response that reduces or eliminates disease symptomswill reduce or stop the spread of a Norovirus outbreak in a population.Vaccine preparation is generally described in Vaccine Design (“Thesubunit and adjuvant approach” (eds Powell M. F. & Newman M. J.) (1995)Plenum Press New York). The compositions of the present invention can beformulated, for example, for administration to a subject by mucosal orparenteral (e.g. intramuscular, intravenous, subcutaneous, intradermal,subdermal, or transdermal) routes of administration. Such mucosaladministration could be, but is not limited to, throughgastro-intestinal, intranasal, oral, or vaginal delivery. In oneembodiment, the vaccine formulation is in the form of a nasal spray,nasal drops or dry powder. In another embodiment, the vaccineformulation is in a form suitable for intramuscular administration.

Vaccine formulations of the invention may be liquid formulations or drypowder formulations. Where the composition is intended for delivery tothe respiratory (e.g. nasal) mucosa, typically it is formulated as anaqueous solution for administration as an aerosol or nasal drops, oralternatively, as a dry powder, e.g. for rapid deposition within thenasal passage. Compositions for administration as nasal drops maycontain one or more excipients of the type usually included in suchcompositions, for example preservatives, viscosity adjusting agents,tonicity adjusting agents, buffering agents, and the like. Viscosityagents can be microcrystalline cellulose, chitosan, starches,polysaccharides, and the like. Compositions for administration as drypowder may also contain one or more excipients usually included in suchcompositions, for example, mucoadhesive agents, bulking agents, andagents to deliver appropriate powder flow and size characteristics.Bulking and powder flow and size agents may include mannitol, sucrose,trehalose, and xylitol.

In one embodiment, the vaccine formulation contains one or morecomposite VLPs as the immunogen, an adjuvant such as MPL®, squalene, orMF59®, a biopolymer such as chitosan or GelSite® to promote adhesion tomucosal surfaces, and bulking agents such as mannitol and sucrose.

For example, a vaccine may be formulated as 10 mg of a dry powdercontaining one or more composite VPLs as discussed herein, such as theGII.4 composite VPL, MPL® adjuvant, chitosan mucoadhesive, and mannitoland sucrose as bulking agents and to provide proper flowcharacteristics. The formulation may comprise about 7.0 mg (25 to 90%w/w range) chitosan, about 1.5 mg mannitol (0 to 50% w/w range), about1.5 mg sucrose (0 to 50% w/w range), about 25 μg MPL® (0.1 to 5% w/wrange), and about 100 μg composite VLP antigen (0.05 to 5% w/w range).

Composite VLPs/antigens may be present in a concentration of from about0.01% (w/w) to about 80% (w/w). In one embodiment, VLPs can beformulated at dosages of about 5 μg, about 15 μg, about 25 μg, about 50μg, about 100 μg, about 200 about 500 μg, and about 1 mg per 10 mg drypowder formulation (0.05, 0.15, 0.25, 0.5, 1.0, 2.0, 5.0, and 10.0% w/w)for administration into both nostrils (10 mg per nostril) or about 10μg, about 30 μg, about 50 μg, about 100 μg, about 200 μg, about 400 μg,about 1 mg, and about 2 mgs (0.1, 0.3, 0.5, 1.0, 2.0, 4.0, 10.0 and20.0% w/w) per 20 mg dry powder formulation for administration into onenostril. The formulation may be given in one or both nostrils duringeach administration. There may be a booster administration 1 to 12 weeksafter the first administration to improve the immune response. Thecontent of each VLP/antigen in the vaccine and antigenic formulationsmay be in the range of 1 μg to 100 mg, preferably in the range 1-1000μg, more preferably 5-500 μb, most typically in the range 10-200 μg.Total VLP/antigen administered at each dose can be either about 10 μg,about 30 μg, about 200 μg, about 250 μg, about 400 μg, about 500 μg, orabout 1000 μg. The total vaccine dose can be administered into onenostril or can be split in half for administration to both nostrils. Drypowder characteristics are such that less than 10% of the particles areless than 10 μm in diameter. Mean particle sizes range from 10 to 500 μmin diameter.

In another embodiment of the invention, the dry powder formulation maybe in combination with one or more devices for administering one or moredoses of the formulation. Such a device may be a single-use nasaladministrative device. In another embodiment, one or more doses are unitdoses.

In some embodiments, the antigenic and vaccine formulations are liquidformulations for subsequent administration to a subject. A liquidformulation intended for intranasal administration would comprisecomposite VLP/antigen(s), adjuvant, and a delivery agent such aschitosan. Liquid formulations for parenteral (e.g., subcutaneous,intradermal, or intramuscular (i.m.)) administration would comprisecomposite VLP/antigen(s), adjuvant, and a buffer, without a deliveryagent (e.g., chitosan).

Preferably the antigenic and vaccine formulations hereinbefore describedare lyophilized and stored anhydrous until they are ready to be used, atwhich point they are reconstituted with diluent. Alternatively,different components of the composition may be stored separately in akit (any or all components being lyophilized). The components may remainin lyophilized form for dry formulation or be reconstituted for liquidformulations, and either mixed prior to use or administered separatelyto the patient. For dry powder administration, the vaccine or antigenicformulation may be preloaded into an intranasal delivery device andstored until use. Preferably, such intranasal delivery device wouldprotect and ensure the stability of its contents.

The invention also encompasses compositions comprising one or more ofthe immunogenic nucleic acids, polypeptides, and/or VLPs, describedherein. Different polypeptides, including composite polypeptides andcapsid polypeptides or fragments thereof may be mixed together in asingle formulation. Within such combinations, an antigen of theimmunogenic composition may be present in more than one polypeptide, ormultiple epitope polypeptide.

The immunogenic compositions may comprise a mixture of compositepolypeptides and nucleic acids encoding composite polypeptides, which inturn may be delivered using the same or different vehicles. Antigens maybe administered individually or in combination, in e.g., prophylactic(i.e., to prevent infection) or therapeutic (to treat infection)immunogenic compositions. The immunogenic composition may be given morethan once (e.g., a “prime” administration followed by one or more“boosts”) to achieve the desired effects. The same composition can beadministered in one or more priming and one or more boosting steps.Alternatively, different compositions can be used for priming andboosting.

The present invention also contemplates a method of inducing protectiveimmunity to a viral infection in a subject comprising administering anyof the vaccine formulations described herein. In one embodiment, theviral infection is a Norovirus infection. In another embodiment, thevaccine formulation confers protection from one or more symptoms ofNorovirus infection.

The present invention also provides a method for making a VLP comprisinga composite polypeptide. In one embodiment, the method comprisesaligning amino acid sequences of capsid proteins from two or morecirculating strains of a non-enveloped virus; determining a consensussequence from said aligned amino acid sequences; preparing a compositesequence based on said consensus sequence that contains at least onedifferent amino acid as compared to each of the capsid sequences of saidtwo or more circulating strains; and expressing said composite sequencein a host cell, thereby producing a virus-like particle. In anotherembodiment, the composite sequence contains at least three differentamino acids as compared to each of the capsid sequences of said two ormore circulating strains. In another embodiment, the composite sequencecontains at least five different amino acids as compared to each of thecapsid sequences of said two or more circulating strains. In yet anotherembodiment, the composite sequence contains at least nine differentamino acids as compared to each of the capsid sequences of said two ormore circulating strains. In some embodiments, the consensus sequencemay be determined from aligning nucleotide sequences of capsid proteinsfrom two or more circulating strains of a non-enveloped virus; andpreparing a composite nucleotide sequence based on said consensussequence. Non-limiting examples of a non-enveloped virus suitable foruse in the method are Calicivirus, Picornavirus, Astrovirus, Adenovirus,Reovirus, Polyomavirus, Papillomavirus, Parvovirus, and Hepatitis Evirus. In some embodiments, the non-enveloped virus is a Calicivirus.The Calicivirus may be a Norovirus or Sapovirus. In another embodiment,the Norovirus is a genogroup I or genogroup II Norovirus.

The invention will now be illustrated in greater detail by reference tothe specific embodiments described in the following examples. Theexamples are intended to be purely illustrative of the invention and arenot intended to limit its scope in any way.

EXAMPLES Example 1 Design of a Norovirus GII.4 Consensus Gene

A consensus amino acid sequence for the major capsid protein (VP1) ofgenogroup II, genotype 4 (GII.4) Norovirus was determined by homologycomparison of two recently circulating GII.4 Strains, Minerva, AKA2006-b, DenHaag, and GenBank Sequence ABL74395; and Laurens, AKA 2006-a,Yerseke, and GenBank Sequence ABL74391, with a GII.4 Houston strain,GenBank Sequence ABY27560, obtained in 2002. The alignment of the threedifferent Norovirus GII.4 isolates is shown below. The consensussequence (SEQ ID NO: 2) determined from the homology comparison of thethree GII.4 strains is shown in FIG. 1.

A composite sequence was derived from the consensus sequence byselecting amino acids from the Laurens sequence in variable positions ofthe consensus sequence where all three strains differed. The chosenamino acids were present in antigenic regions near to but not includingthe proposed carbohydrate binding domain. The composite GII.4 sequencewas used for the production of a synthetic gene encoding a compositeGII.4 Norovirus VP1 protein (SEQ ID NO: 1). The GII.4 composite VP1amino acid sequence (GII.4 Comp) is shown in the alignment below as SEQID NO: 1 with the amino acid sequences of the VP1 proteins from Houston,Laurens, and Minerva virus (SEQ ID NOs: 4, 5, and 6, respectively). TheDNA sequence encoding the GII.4 composite VP1 (SEQ ID NO: 3) is shown inFIG. 2.

Example 2 Purification of Composite VLPs

Synthetic gene construct of Norovirus GII.4 composite sequence forcapsid domains described in Example 1 was cloned into recombinantBaculovirus. Infection of insect cells demonstrated high yield ofproduction of VLP. A 40 mL aliquot of a P2 pFastBac recombinantbaculovirus stock for the composite VLP VP1 gene was processed with asucrose gradient to verify the expression and assembly of compositeVLPs. The conditioned media was first layered onto a 30% sucrose cushionand then centrifuged at 140 K×g to pellet the VLP. The pellet wasresuspended, layered onto a sucrose gradient and then centrifuged at 140K×g. A visible white layer was observed within the gradient aftercentrifugation. 500 μL fractions from the gradient were collected andthen analyzed by SDS-PAGE/Coomassie gel (FIG. 3). The expected bandingpattern for composite VLP at ˜56 kDa was observed within the sucrosegradient fractions.

Using a high pressure liquid chromatography system with a running bufferof 20 mM Tris 150 mM NaCl pH 7 at a flow rate of 0.5 mL/minute, a 50 μLaliquot of the composite expression cell culture supernatant was loadedon to a Superose-6 size exclusion column. An intact VLP peak wasobserved at ˜15.3 minutes at 280 nm and 220 nm confirming integrity ofthe composite VLPs (FIG. 4).

Composite VLPs were also purified from conditioned media using columnchromatography. Conditioned media was processed by cation exchangechromatography. The cation exchange elution fraction was furtherpurified by hydrophobic interaction chromatography (HIC). The HICelution fraction was concentrated and buffer exchanged by tangentialflow filtration. The final product was sterile filtered and stored at 4°C. 500 ng of the purified composite VLPs (CM3 lot) was analyzed bysilver-stained SDS-PAGE (FIG. 5).

Using a high pressure liquid chromatography system with a running bufferof 20 mM Tris 150 mM NaCl pH 7 at a flow rate of 1.0 mL/minute, a 50 μLaliquot of the purified CM3 composite VLPs was loaded on to a Superose-6size exclusion column. An intact VLP peak was observed at ˜7.5 minutesat 280 nm confirming integrity of the composite VLPs (FIG. 6).

Example 3 Composite Immunogenicity

Female C57BL/6 mice approximately 8-10 weeks of age were immunizedintraperitoneally with decreasing concentrations of composite VLP (CVLP)starting with 50 μg and decreasing 2 fold to 0.19 μg. The CVLP containeda polypeptide having the sequence of SEQ ID NO: 1 as described inExample 1. A group of animals immunized with PBS alone was included as anegative control. Serum samples were collected and analyzed for thepresence of CVLP-specific IgG by ELISA (FIG. 7). The results from thisexperiment indicate that the linear range of the dose curve is betweenapproximately 6 μg and 0.2 μg. Doses above 6.25 μg of CVLP do not appearto enhance immune responses in a dose-dependent manner. The EC₅₀ value(defined as the effective dose yielding a 50% response) was calculatedto be approximately 1.0 μg/mL using Softmax Pro software (MolecularDevices Corporation, Sunnyvale, Calif.).

Example 4 Multiple Antigen Effect of Composite VLPs

Female C57BL/6 mice (8-10 weeks of age) were immunized intraperitoneallywith varying doses of either Norwalk VLP alone (NVLP), composite VLP(CVLP) alone or in combination. A group of animals immunized with PBSalone was included as a negative control. Serum samples were collectedand analyzed for the presence of antigen-specific IgG by ELISA (FIGS. 8and 9). The results indicate that immunizing with the combination of theCVLP and NVLP enhances the immune response such that a higher IgG levelis achieved with a lower dose of antigen. For example, immunizing with 1μg of each NVLP and CVLP elicits a more robust immune response thenadministering with either VLP alone. The antibodies from animalsimmunized with CVLP did not cross-react with NVLP and vise versa (datanot shown).

Example 5 Composite VLPs Elicit Cross-Reactivite Antibodies

Female C57/BL6 mice, approximately 10-12 weeks of age, were immunizedintraperitoneally with either 30 μg Houston VLPs or composite VLPsformulated with MPL (20 μg) as an adjuvant. The composite VLPs containeda polypeptide having the sequence of SEQ ID NO: 1 as described inExample 1. The mice were bled on day 21 following immunization and thesera were assayed in an antigen-specific ELISA to determine antibodytiters for composite, Houston, Laurens, and Norwalk VLPs. The data areshown in FIG. 10. Immunization with composite VLP induces a broaderresponse across more serotypes as evidenced by the greater response tothe Laurens strain while maintaining response to the Houston strain.Immunization with Houston VLPs also induces cross-reactive antibodiesagainst composite and Laurens but the magnitude of the response is notas great as that observed with immunization with the composite VLPs.There was no detectable response to Norwalk VLP, which is a GI.1Norovirus.

Example 6 Efficacy of Bivalent Vaccine in Rabbits

A study was performed to evaluate the efficacy of a bivalent Norovirusvaccine comprising Norovirus GII.4 composite VLPs (CVLPS) as describedin Example 2 and Norwalk VLPs (NVLPs, GI.1). Rabbits wereintramuscularly immunized with this bivalent vaccine on days 0 and 21.VLP doses ranged from 20 μg to 0.002 μg of each type of VLP and eachvaccine formulation contained 25 μg MPL and 250 μg AlOH. Serum wascollected from each rabbit on day 28 and VLP-specific IgG was evaluated.Spleens and mesenteric lymph nodes were collected on day 75 andevaluated for the presence antigen-specific cellular immunity.

Serum IgG titers were measured by ELISA using microtiter plates coatedwith either NVLP or CVLP as a capture. Titers are expressed asreciprocal dilutions (FIG. 11). Antigen-specific T-cell responsivenesswas evaluated by tritiated thymidine incorporation after a 5-day invitro stimulation with 5 μg of either NVLP or CVLP (FIG. 12). MemoryB-cells were evaluated by VLP-specific ELISPOT and results are expressedas antibody-secreting cells per million cells (FIG. 13).

The results of this study demonstrate that the IM bivalent norovirusvaccine formulated with the adjuvants MPL and AlOH elicits highVLP-specific IgG responses, responsive T-cells and memory B-cellscapable of responding to stimulation with both NVLP and CVLP.

Example 7 High-Dose Bivalent Vaccination in Rabbits

This example outlines experiments designed to determine if high doses ofthe composite and Norwalk VLPs in the bivalent vaccine would lead to anyadverse events. Rabbits were intramuscularly immunized with the bivalentvaccine (see Example 6) on days 0, 14, and 21. VLP doses ranged from 150μg to 5 μg of each VLP (Norwalk and composite) and each formulationcontained 50 μg MPL and 500 μg AlOH. The general health, coat condition,and injection site of the immunized rabbits were monitored every 12hours for the first 72 hours and then daily thereafter. Serum wascollected from each rabbit on day 21 and day 35 and Norwalk VLP(NVLP)-specific (FIG. 14) and composite VLP (CVLP)-specific (FIG. 15)IgG and IgA were evaluated. Spleens were also harvested on day 35 andevaluated for the presence of antigen-specific cellular immunity (FIG.16).

Serum IgG titers were measured by ELISA using microtiter plates coatedwith either NVLP or CVLP as a capture. Titers are expressed asreciprocal dilutions. Antigen-specific T-cell responsiveness wasevaluated by tritiated thymidine incorporation after a 5-day in vitrostimulation with the indicated antigens (e.g. composite VLPs, GII.4(2002) VLPs, GII.4 (2006 VLPs, and Norwalk VLPs).

The results from this study shows that the Norovirus bivalent vaccine issafe at the tested doses as evidenced by the fact that all rabbitsappeared healthy throughout the study duration and no injection sitereactions were observed. The immune responses measured from vaccinatedrabbits confirm that the bivalent Norovirus vaccine is effective foreliciting both VLP-specific antibodies as well as VLP-responsiveT-cells.

Example 8 Mouse Potency Assay for Norovirus Vaccine Efficacy

This example outlines the development of a mouse potency assay toevaluate the potency of the bivalent Norovirus vaccine. Mice wereimmunized IP on day 0 and 7 with equal concentrations ranging from 0.002μg to 30 μg of Norwalk VLP (NVLP) and composite VLP (CVLP). Serum wascollected from each mouse on day 14 and VLP-specific IgG was evaluated(FIG. 17). The neutralizing activity of the antibodies was also measuredby hemagglutination inhibition assay (HAI) using Type O positive humanred blood cells (FIG. 18). Only Norwalk-specific HAI titers could beassessed because the GII.4 genotypes do not hemagglutinate red bloodcells.

Serum IgG titers were measured by ELISA using microtiter plates coatedwith either NVLP or CVLP as a capture. Titers are expressed asreciprocal dilutions. HAI titers were measured by using a standardhemagglutination assay.

The results from this study indicate that vaccination with the bivalentNorovirus vaccine elicits potent and functional IgG titers such thatthey are capable of inhibiting hemagglutination of human red bloodcells. These results are of particular importance because theydemonstrate that the antibodies elicited in response to the vaccinationhave functionality, which may lead to neutralization of the actual virusduring an infection.

Example 9 Chitosan Formulations of a Norovirus Bivalent Vaccine

A study was performed in rabbits with the bivalent Norovirus VLP vaccineto evaluate the role of chitosan in this vaccine formulation. Theformulation contained equal amounts of a Norwalk VP1 VLP and a compositeGII.4 VLP (see Example 2). Rabbits were intranasally immunized with drypowder formulations on days 0 and 21. VLP doses ranged from 150 μg to 5μg of each type of VLP and each formulation contained 50 μg MPL.Chitosan concentration was varied for each dose range (7 mg, 0.7 mg and0 mg) to determine its role in immunogenicity. Serum was collected fromeach rabbit and VLP-specific IgG was evaluated (FIG. 19).

Serum IgG titers were measured by ELISA using microtiter plates coatedwith VLP as a capture. Serial dilutions of a proprietary in-house rabbitanti-VLP serum were used to generate standard curves. Titers areexpressed in Units anti-VLP/mL (one Unit is approximately equal to 1μg).

Results from these experiments indicate that chitosan at the highestdose (7 mg) is required to achieve maximum immunogenicity. The IgG datafor the 50 μg dose is shown in FIG. 19 and results are represented asU/ml. The IgA antibody response is shown below in Table 1.

TABLE 1 Antigen-Specific IgA Responses. VLP 50 50 50 (μg) Chitosan 7 0.70 (mg) Geometric Mean 770 (474, 1253) 67 (32, 142) 83 (38, 179) IgATiters (95% CI)

Example 10 Design of a Norovirus GII Consensus Gene

The methods of the present invention may also be used to generate capsidconsensus sequences amongst Norovirus GII isolates from different GIIgenotypes, GII.1, GII.2, GII.3. The following alignment was generatedfrom VP1 sequences from three different Norovirus GII isolates. Theconsensus sequence (SEQ ID NO: 7) determined from the homologycomparison of the three GII strains is shown in FIG. 20.

A composite sequence is derived from the consensus sequence by selectingamino acids from a sequence of one of the strains for variable positionsof the consensus sequence where two or more strains differ. Preferablythe sequence from which amino acids are selected is a recentlycirculating strain, or a strain that is more commonly associated withdisease or more commonly occurring amongst the strains being evaluated.In this Example, amino acids were selected from the Snow Mountainsequence at variable positions of the consensus sequence at which allthree strains differed to generate a composite VP1 GII sequence. Thecomposite GII sequence is used for production of a synthetic geneencoding a composite GII VP1 protein for induction of cross-immunityamongst GII Norovirus isolates.

The composite GII VP1 amino acid sequence (Composite) is shown in thealignment below as SEQ ID NO: 11 with the amino acid sequences of theVP1 proteins from GII.1 (Accession Number: AAL13001), GII.2 SnowMountain (Accession Number: AAB61685), and GII.3 virus (AccessionNumber: AAL12998) (SEQ ID NOs: 8, 9, and 10, respectively).

Example 11 Design of a Norovirus GI Consensus Gene

The methods of the present invention may also be used to generate capsidconsensus sequences amongst Norovirus GI isolates. The followingalignment was generated from VP1 sequences from three differentNorovirus GI isolates. The consensus GI sequence (SEQ ID NO: 12)determined from the homology comparison of the three GI strains is shownin FIG. 21.

A composite sequence is derived from the consensus sequence by selectingamino acids from a sequence of one of the strains for variable positionsof the consensus sequence where two or more strains differ. Preferablythe sequence from which amino acids are selected is a recentlycirculating strain, or a strain that is more commonly associated withdisease or more commonly occurring amongst the strains being evaluated.In this Example, amino acids were selected from the Southampton sequenceat variable positions of the consensus sequence at which all threestrains differed to generate a composite VP1 GI sequence. The compositeGI sequence is used for production of a synthetic gene encoding acomposite GI VP1 protein for induction of cross-immunity amongst GINorovirus isolates.

The composite GI VP1 amino acid sequence (Composite) is shown in thealignment below as SEQ ID NO: 16 with the amino acid sequences of theVP1 proteins from Norwalk virus (Accession Number: M87661), Southampton(Accession Number: Q04542), and Chiba virus (Accession Number: BAB18267)(SEQ ID NOs: 13, 14, and 15, respectively).

Example 12 Design of a Human Papillomavirus Consensus Gene for L1

The methods of the present invention may also be used to generateconsensus sequences amongst other non-enveloped viruses. The followingalignment was generated from three Human Papillomavirus (HPV): HPV-11,HPV-16, and HPV-18. The consensus L1 capsid protein sequence (SEQ ID NO:17) determined from the homology comparison of the three HPV strains isshown in FIG. 22.

A composite sequence is derived from the consensus sequence by selectingamino acids from a sequence of one of the strains for variable positionsof the consensus sequence where two or more strains differ. Preferablythe sequence from which amino acids are selected is a recentlycirculating strain, or a strain that is more commonly associated withdisease or more commonly occurring amongst the strains being evaluated.In this Example, amino acids were selected from the HPV-18 sequence atvariable positions of the consensus sequence at which all three strainsdiffered to generate a composite L1 HPV sequence. The composite HPVsequence is used for production of a synthetic gene encoding a compositeL1 polypeptide for induction of cross-immunity amongst a variety of HPVstrains.

The composite HPV L1 amino acid sequence (Composite) is shown in thealignment below as SEQ ID NO: 21 with the amino acid sequences of the L1proteins from HPV-11, HPV-16, and HPV-18 virus (SEQ ID NOs: 18, 19, and20, respectively).

Example 13 Dose Escalation Safety Study of Composite VLP VaccineFormulation in Humans

A double-blind, controlled, dose-escalation phase 1 study of the safetyand immunogenicity of a Norovirus vaccine is conducted. The vaccineconsists of composite Norovirus virus-like particles (VLPs) in a drypowder matrix designed for intranasal administration. The composite VLPscontain a polypeptide having the amino acid sequence of SEQ ID NO: 1.Vaccines include healthy adult volunteers who are H type 1 antigensecretors. The rationale for enrollment of H type 1 antigen secretors isthat H type 1 antigen secretors are susceptible to Norovirus infectionswhile non-secretors are resistant. As a control, 2 additional volunteersat each dosage level receive matrix alone. The dry powder matrixincludes 25 MPL® adjuvant, 7 mg chitosan, 1.5 mg mannitol, and 1.5 mgsucrose. Volunteers are dosed on days 0 and 21 and are required to keepa 7-day diary of symptoms after each dose. Blood for serology, antibodysecreting cells (ASC), and stool and saliva samples for mucosal antibodyevaluation are collected.

The components of the vaccine are listed in Table 2. The vaccine ispackaged in an intranasal delivery device. Single administrations of thecomposite VLP vaccine are packaged in a single dose Bespak (MiltonKeynes, UK) UniDose DP dry powder intranasal delivery device. Eachdevice delivers 10 mg of the dry powder vaccine formulation. Each doseof vaccine consists of two delivery devices, one in each nostril. Thetotal vaccine dose is 20 mg of dry power. The formulation ofAdjuvant/Excipient is the same as the composite VLP vaccine except thatno composite VLP antigen is included in the formulation. The formulationof the Adjuvant/Excipient (also referred to as dry powder matrix) issummarized in Table 3.

TABLE 2 Composite VLP Vaccine Composition Quantity per 10 mg dry % ofFinal Component Molecular class powder Formulation Composite VLPRecombinant 2.5, 7.5 or 0.025, 0.075, protein 25, 50 μg 0.25, or 50%Monophosphoryl Phospholipid 25 μg 0.25%   Lipid A ChitosanPolysaccharide 7.0 mg 70% Mannitol Sugar 1.5 mg  15%* Sucrose Sugar 1.5mg 15%

TABLE 3 Adjuvant/Excipient (dry powder matrix) Quantity per 10 mg dry %of Final Component Molecular class powder Formulation MonophosphorylPhospholipid 25 μg 0.25%  Lipid A Chitosan Polysaccharide 7.0 mg 70%Mannitol Sugar 1.5 mg 15% Sucrose Sugar 1.5 mg 15%

Specifically, the dose escalation of the vaccine is conducted asfollows: After appropriate screening for good health, a group of 3volunteers is randomized to receive either 5 μg of the composite VLPvaccine plus dry powder matrix (n=2) or dry powder matrix alone (n=1) bythe intranasal route. These 3 volunteers are followed for safety for 21days, and the Independent Safety Monitor (ISM) reviews their safetydata. After approval of the ISM, these individuals receive their seconddose of vaccine or matrix on day 21, and 4 additional volunteers arerandomized to receive either 5 μg VLP protein plus dry powder matrix(n=3) or matrix alone (n=1) by the intranasal route. The ISM reviews thesafety data from this second group and after approval of the ISM, thesecond intranasal dose is given 21 days after the first dose. Volunteerskeep a 7-day diary of symptoms after each dose. After the ISM determinesthat escalation to the next higher dose is acceptable, another group of7 volunteers is randomized to receive either the composite VLP vaccinecontaining 15 μg VLP protein (n=5) or dry powder matrix alone (n=2) bythe intranasal route at day 0 and day 21. Again, 7-day symptom diariesare recorded and reviewed by the ISM before the second dose at day 21.Finally, after review of the safety data from the first two dosagecohorts, the ISM determines if dose escalation is acceptable and a finalgroup of 7 volunteers is randomized to receive either the composite VLPvaccine containing 50 μg VLP protein (n=5) or dry powder matrix alone(n=2) by the intranasal route on day 0 and day 21. Again, the ISMreviews seven-day symptom diaries and other safety data before thesecond dose at day 21.

The volunteers keep a daily diary of symptoms (including local symptomssuch as: nasal discharge, nasal pain/discomfort, nasal congestion, runnynose, nasal itching, nose bleed, headache and systemic symptoms such as:daily oral temperature, myalgia, nausea, vomiting, abdominal cramps,diarrhea, and loss of appetite) for 7 days after receiving the compositeVLP vaccine or dry powder matrix alone. Interim medical histories areobtained at each follow-up visit (days 7±1, 21±2, 28±2, 56±2 and180±14); volunteers are queried about interim illness, medications, anddoctor's visits. Volunteers are asked to report all serious or severeadverse events including events that are not solicited during follow upvisits. Volunteers have CBC and serum creatinine, glucose, AST, and ALTassessed on days 7 and 28 (7 days after each immunization) and, ifabnormal, the abnormal laboratory test is followed until the testbecomes normal or stabilizes.

Blood is collected before immunization and on days 7±1, 21±2, 28±2,56±2, and 180±14 to measure serum antibodies to the composite VLPvaccine by enzyme-linked immunosorbent assays (ELISA). Before and on day7 after administration of each dose of vaccine or dry powder matrixalone peripheral blood lymphocytes are collected to detect antibodysecreting cells by ELISPOT assay. Before and on days 21±2, 56±2 and180±14 after vaccination, whole blood is obtained to separate cells andfreeze for future studies of cell mediated immunity, including cytokineproduction in response to composite VLP antigen, andlymphoproliferation. Whole stool samples are collected beforeimmunization and on days 7±1, 21±2, 28±2, 56±2, and day 180±14 foranti-composite VLP sIgA screening. Saliva is collected with acommercially available device (Salivette, Sarstedt, Newton, N.C.) beforeimmunization and on days 7±1, 21±2, 28±2, 56±2, and if positive formucosal antibodies at day 56, a day 180±14 sample is collected andscreened for anti-composite VLP sIgA. Finally blood from volunteersreceiving the highest dose of composite VLPs (50 μg, third cohortdescribed above) is screened for memory B-cells on days 0, 21, 56 and180.

The following methods are used to analyze the blood, stool, and salivasamples collected from immunized individuals or individuals receivingthe dry powder matrix alone:

A. Serum Antibody Measurements by ELISA

Twenty mL of blood are collected before and at multiple time pointsafter vaccination for measurement of antibodies to the composite VLP byELISA, using purified recombinant composite VLPs as target antigen toscreen the coded specimens. Briefly, composite VLPs in carbonate coatingbuffer pH 9.6 are used to coat microtiter plates. Coated plates arewashed, blocked, and incubated with serial two-fold dilutions of testserum followed by washing and incubation with enzyme-conjugatedsecondary antibody reagents specific for human IgG, IgM, and IgA.Appropriate substrate solutions are added, color developed, plates read,and the IgG, IgM, and IgA endpoint titers are determined in comparisonto a reference standard curve for each antibody class. A positiveresponse is defined as a 4-fold rise in titer after vaccination.

B. Antibody Secreting Cell Assays

Peripheral blood mononuclear cells (PMBCs) are collected from thirty mLof heparinized blood for ASC assays to detect cells secreting antibodiesto composite VLPs. These assays are performed on days 0, 7±1, 21±2, and28±2 after administration of the composite VLP vaccine or dry powdermatrix alone. A positive response is defined as a post-vaccination ASCcount per 10⁶ PBMCs that is at least 3 standard deviations (SD) abovethe mean pre-vaccination count for all subjects (in the log metric) andat least 8 ASC spots, which corresponds to the mean of medium-stimulatednegative control wells (2 spots) plus 3 SD as determined in similarassays.

C. Measurement of Composite VLP-Specific Memory B-Cells

Heparinized blood is collected from cohort 3 (30 mL days 0 and 21, 50 mLdays 56 and 180) to measure memory B cells on days 0, 21, 56 and 180after vaccination using an ELISpot assay preceded by an in vitro antigenstimulation. A similar assay was successfully used to measure frequencyof memory B cells elicited by Norwalk VLP formulations in rabbits (SeeWO 2008/042789, herein incorporated by reference in its entirety).Peripheral blood mononuclear cells (5×10⁶ cells/mL, 1 mL/well in 24-wellplates) are incubated for 4 days with composite VLP antigen (2-10 μg/mL)to allow for clonal expansion of antigen-specific memory B cells anddifferentiation into antibody secreting cells. Controls include cellsincubated in the same conditions in the absence of antigen and/or cellsincubated with an unrelated antigen. Following stimulation, cells arewashed, counted and transferred to ELISpot plates coated with compositeVLP. To determine frequency of VLP-specific memory B cells per totalIg-secreting B lymphocytes, expanded B cells are also added to wellscoated with anti-human IgG and anti-human IgA antibodies. Boundantibodies are revealed with HRP-labeled anti-human IgG or anti-humanIgA followed by True Blue substrate. Conjugates to IgA and IgGsubclasses (IgA1, IgA2 and IgG1-4) may also be used to determineantigen-specific subclass responses which may be related with distincteffector mechanisms and locations of immune priming. Spots are countedwith an ELISpot reader. The expanded cell populations for each volunteerare examined by flow cytometry to confirm their memory B cell phenotype,i.e. CD19+, CD27+, IgG+, IgM+, CD38+, IgD

D. Cellular Immune Responses

Heparinized blood (50 mL cohorts 1 and 2, 25 mL cohort 3) is collectedas coded specimens and the PBMCs isolated and cryopreserved in liquidnitrogen for possible future evaluation of cell-mediated immune (CMI)responses to composite VLP antigen. Assays that may be performed includePBMC proliferative and cytokine responses to composite VLP antigen andcan be determined by measuring interferon (IFN)-γ and interleukin (IL)-4levels according to established techniques.

E. Collections of Stool and Saliva for Anti-Composite VLP sIgA

Anti-composite VLP IgA is measured in stool and saliva samples. Salivaspecimens are treated with protease inhibitors (i.e. AEBSF, leupeptin,bestatin, and aprotinin) (Sigma, St. Louis, Mo.), stored at −70° C., andassayed using a modification of a previously described assay (Mills etal. (2003) Infect. Immun. 71: 726-732). Stool is collected on multipledays after vaccination and specimens stored at −70° C. until analysis.The specimens are thawed, and protease inhibitor buffer added to preparea 10% w/v stool suspension. Stool supernatants are assayed for compositeVLP-specific mucosal IgA by ELISA, as described below.

Approximately 2-3 mL of whole saliva is collected before and at multipletime points after vaccination. Saliva is collected by a commerciallyavailable device (Salivette, Sarstedt, Newton, N.C.), in which aSalivette swab is chewed or placed under the tongue for 30-45 secondsuntil saturated with saliva. Saliva is collected from the swab bycentrifugation.

F. Measurement of Anti-Composite VLP in Stool and Saliva

ELISAs, utilizing plates coated with either anti-human IgA antibodyreagents or target composite VLP antigen coatings, are performed todetermine total IgA and to titer the specific anti-VLP IgA responses foreach specimen. Total or specific IgA are revealed with HRP-labeledanti-human IgA as described above. An internal total IgA standard curveis included to quantify the IgA content. Response is defined as a 4-foldrise in specific antibody.

Example 14 Safety and Immunogenicity Study of Two Dosages of IntranasalComposite VLP Vaccine in Humans

A randomized, double blind study in healthy adults is conducted tocompare the safety and immunogenicity of two dosage levels of acomposite Norovirus virus-like particle (VLP) vaccine withadjuvant/excipients and placebo controls (empty device). The vaccineconsists of composite Norovirus virus-like particles (VLPs) in a drypowder matrix designed for intranasal administration as described inExample 13. Vaccines include healthy adult volunteers who are H type 1antigen secretors. The human volunteers are randomly assigned to one offour groups and each group receives one of the following treatments: a50 mg dose of the composite VLP vaccine, a 100 μg dose of the compositeVLP vaccine, the adjuvant/excipient, or placebo. Volunteers are dosed ondays 0 and 21 and are required to keep a 7-day diary of symptoms aftereach dose. Blood for serology, antibody secreting cells (ASC), and stooland saliva samples for mucosal antibody evaluation are collected.

The components of the vaccine are listed in Table 2 in Example 13. Thevaccine is packaged in an intranasal delivery device. Singleadministrations of the composite VLP vaccine are packaged in a singledose Bespak (Milton Keynes, UK) UniDose DP dry powder intranasaldelivery device. Each device delivers 10 mg of the dry powder vaccineformulation. Each dose of vaccine consists of two delivery devices, onein each nostril. The total vaccine dose is 20 mg of dry power.Therefore, the 50 μg vaccine dose consists of two devices that eachdeliver 10 mg of dry powder formulation, wherein each 10 mg of drypowder formulation consists of 25 μg of composite VLP, 25 μg MPL®adjuvant, 7 mg chitosan, 1.5 mg mannitol, and 1.5 mg sucrose. Similarly,the 100 μg vaccine dose consists of two devices that each deliver 10 mgof dry powder formulation, wherein each 10 mg of dry powder formulationconsists of 50 μg of composite VLP, 25 μg MPL® adjuvant, 7 mg chitosan,1.5 mg mannitol, and 1.5 mg sucrose. The formulation ofAdjuvant/Excipient is the same as the composite VLP vaccine except thatno composite VLP antigen is included in the formulation. The formulationof the Adjuvant/Excipient (also referred to as dry powder matrix) issummarized in Table 3 in Example 13. The placebo group receives twoempty devices.

The volunteers keep a daily diary of symptoms (including local symptomssuch as: nasal discharge, nasal pain/discomfort, nasal congestion, runnynose, nasal itching, nose bleed, headache and systemic symptoms such as:daily oral temperature, myalgia, nausea, vomiting, abdominal cramps,diarrhea, and loss of appetite) for 7 days after receiving either one oftwo doses of the composite VLP vaccine, dry powder matrix alone, or theplacebo. Interim medical histories are obtained at each follow-up visit(days 7±1, 21±2, 28±2, 56±2 and 180±14); volunteers are queried aboutinterim illness, medications, and doctor's visits. Volunteers are askedto report all serious or severe adverse events including events that arenot solicited during follow up visits. Volunteers have CBC and serumcreatinine, glucose, AST, and ALT assessed on days 7 and 28 (7 daysafter each immunization) and, if abnormal, the abnormal laboratory testis followed until the test becomes normal or stabilizes.

Blood is collected before immunization and on days 7±1, 21±2, 28±2,56±2, and 180±14 to measure serum antibodies to the composite VLPvaccine by enzyme-linked immunosorbent assays (ELISA). Before and on day7 after administration of each dose of vaccine, dry powder matrix alone,or placebo, peripheral blood lymphocytes are collected to detectantibody secreting cells by ELISPOT assay. Before and on days 21±2, 56±2and 180±14 after vaccination, whole blood is obtained to separate cellsand freeze for future studies of cell mediated immunity, includingcytokine production in response to composite VLP antigen, andlymphoproliferation. Whole stool samples are collected beforeimmunization and on days 7±1, 21±2, 28±2, 56±2, and day 180±14 foranti-composite VLP sIgA screening. Saliva is collected with acommercially available device (Salivette, Sarstedt, Newton, N.C.) beforeimmunization and on days 7±1, 21±2, 28±2, 56±2, and if positive formucosal antibodies at day 56, a day 180±14 sample is collected andscreened for anti-composite VLP sIgA. Blood is also screened for memoryB-cells on days 0, 21, 56 and 180.

Methods used to analyze the blood, stool, and saliva samples collectedfrom immunized individuals, or individuals receiving the dry powdermatrix alone or placebo are described in detail in Example 13.

Example 15 Experimental Human Challenge Study with Infectious NorovirusFollowing Vaccination with Composite Norovirus VLP Vaccine

A multi-site, randomized, double-blind, placebo-controlled Phase 1-2challenge study is conducted in 80 human volunteers immunized with thecomposite Norovirus VLP vaccine. Eligible subjects include those 18-50years of age, in good health, who express the H type-1 oligosaccharide(as measured by positive salivary secretor status) and who are otherthan Type B or AB blood type. Subjects who are non H type-1 secretors orwho have Type B or AB blood are reported to be more resistant toinfection with Norwalk virus and are excluded from the study. At least80% of volunteers are expected to be eligible based on these twocriteria.

Following screening, eligible volunteers who meet all acceptancecriteria are randomized (1:1) into one of two equal sized cohorts withapproximately 40 volunteers in each cohort. Cohort 1 is immunized withcomposite VLP and cohort 2 receives placebo. Volunteers are immunizedwith 10 mg composite VLP vaccine in each nostril (20 mg total drypowder) or placebo. Each 10 mg of composite VLP vaccine contains 50 μgof Composite VLP, 7 mg chitosan, 25 μg MPL®, 1.5 mg of sucrose andapproximately 1.5 mg of mannitol. Thus, each volunteer in cohort 1receives a total dosage of 100 μg of composite VLP antigen at eachimmunization. Volunteers receive vaccine or placebo on study days 0 and21.

The safety of the composite virus VLP vaccine compared to placebo isassessed. Volunteers keep a diary for 7 days following each immunizationwith the vaccine or placebo to document the severity and duration ofadverse events. Serious adverse events (SAEs) and the occurrence of anysignificant new medical conditions is followed for 6 months after thelast dose of vaccine or placebo and for 4 months after the challengewith infectious virus.

All volunteers are challenged with infectious Norovirus between 21 to 42days after the second dose of vaccine or placebo (between study days 42and 56). Each volunteer receives at or >than the 50% Human InfectiousDose (HID 50), i.e. the amount of infectious virus that is expected tocause disease in at least 50% of volunteers in the placebo group. TheHID 50 is between about 48 and about 480 viral equivalents of thechallenge virus strain. The challenge Norovirus is mixed with sterilewater and given orally. The inoculation is preceded by ingestion of 500mg sodium bicarbonate in water, to prevent breakdown of the virus bystomach acid and pepsin. A second ingestion of sodium bicarbonatesolution (500 mg sodium bicarbonate in water) is taken 5 minutes afteroral inoculation of the infectious virus. The volunteers remain at thechallenge facility for at least 4 days and at least 18 hours aftersymptoms/signs of acute gastroenteritis (vomiting, diarrhea, loosestool, abdominal pain, nausea, and fever) are absent.

Several metrics are monitored to determine the efficacy of the compositeVLP vaccine in preventing or reducing symptoms/signs of acutegastroenteritis induced by the viral challenge. All volunteers recordtheir clinical symptoms of acute gastroenteritis and these symptoms aredocumented by the research staff at the study sites. Diseasesymptoms/signs from cohort 1 receiving the vaccine are compared tocohort 2 placebo recipients.

Sera and stool samples are routinely collected from all volunteers priorto immunization with the vaccine or placebo, and after challenge. Serumsamples are analyzed by ELISA for IgA and IgG, titers against thechallenge VLPs. The challenge virus antigen and challenge virus RNA aretested in stool samples by ELISA and PCR, respectively, which indicatethe presence of virus, the amount of virus shed from the intestines, andthe duration of viral shedding. Subjects who become ill after challenge,are subject to additional laboratory studies including serumchemistries, BUN, creatinine, and liver function tests untilsymptoms/signs resolve.

Results from the vaccine group (cohort 1) and the placebo group (cohort2) are compared to assess the protective efficacy of the vaccine againstNorovirus disease overall (primary endpoint), and/or its efficacy inameliorating the symptoms/signs (severity and # of days of illness)and/or the reduction of the presence, the amount and/or the duration ofvirus shedding (secondary endpoints).

The present invention is not to be limited in scope by the specificembodiments described which are intended as single illustrations ofindividual aspects of the invention, and functionally equivalent methodsand components are within the scope of the invention. Indeed, variousmodifications of the invention, in addition to those shown and describedherein, will become apparent to those skilled in the art from theforegoing description and accompanying drawings using no more thanroutine experimentation. Such modifications and equivalents are intendedto fall within the scope of the appended claims.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated by reference into thespecification to the same extent as if each individual publication,patent or patent application was specifically and individually indicatedto be incorporated herein by reference.

Citation or discussion of a reference herein shall not be construed asan admission that such is prior art to the present invention.

The invention claimed is:
 1. A virus-like particle comprising at leastone polypeptide having a composite amino acid sequence, wherein saidcomposite amino acid sequence comprises SEQ ID NO: 1 or SEQ ID NO: 22,and wherein the at least one polypeptide forms a virus-like particlewhen expressed in a host cell.
 2. The virus-like particle of claim 1,wherein the virus-like particle has antigenic properties of two or morecirculating strains of a non-enveloped virus.
 3. The virus-like particleof claim 1, wherein the virus-like particle provides at least a two-foldincrease in antisera cross-reactivity to one or more circulating strainsof a non-enveloped virus as compared to the antisera cross-reactivityobtained by immunizing with a virus-like particle containing onlyprotein from said one or more circulating strains.
 4. The virus-likeparticle of claim 1, further comprising a second polypeptide having asecond composite amino acid sequence, wherein said second compositeamino acid sequence is derived from a consensus sequence representingthe capsid proteins of two or more circulating strains of a secondCalicivirus, wherein the second composite sequence is derived from theconsensus sequence by selecting, at each variable position where thecapsid protein sequences of said two or more circulating strains differ,an amino acid present at that position in one of the said capsid proteinamino acid sequences, wherein the composite sequence contains at least 1different amino acid as compared to each of the capsid sequences of saidtwo or more circulating strains of the second Calicivirus.
 5. Thevirus-like particle of claim 4, wherein the composite sequence contains5-50 different amino acids compared to the capsid sequence of one ormore circulating strains of the second Calicivirus.
 6. The virus-likeparticle of claim 4, wherein the second Calicivirus is a Norovirus. 7.The virus-like particle of claim 6, wherein the Norovirus is a genogroupI Norovirus.
 8. The virus-like particle of claim 7, wherein thegenogroup I Norovirus is selected from the group consisting of Norwalkvirus, Southampton virus, Hesse virus, and Chiba virus.
 9. Thevirus-like particle of claim 4, wherein the virus-like particle hasantigenic properties of the two or more circulating strains of the firstCalicivirus and the two or more circulating strains of the secondCalicivirus.
 10. The virus-like particle of claim 1, wherein thepolypeptide comprises a composite amino acid sequence encoded by anucleic acid sequence of SEQ ID NO:
 3. 11. A vaccine formulationcomprising the virus-like particle of claim
 1. 12. A vaccine formulationcomprising the virus-like particle of claim 1 and a second virus-likeparticle, wherein said second virus-like particle comprises a capsidprotein from a Norovirus.
 13. The vaccine formulation of claim 12,wherein said Norovirus is a genogroup I or genogroup II Norovirus. 14.The vaccine formulation of claim 11 further comprising an adjuvant. 15.The vaccine formulation of claim 14, wherein the adjuvant is selectedfrom the group consisting of toll-like receptor (TLR) agonists,monophosphoryl lipid A (MPL), synthetic lipid A, lipid A mimetics oranalogs, aluminum salts, cytokines, saponins, muramyl dipeptide (MDP)derivatives, CpG oligos, lipopolysaccharide (LPS) of gram-negativebacteria, polyphosphazenes, emulsions, virosomes, cochleates,poly(lactide-co-glycolides) (PLG) microparticles, poloxamer particles,microparticles, liposomes, oil-in-water emulsion, MF59, and squalene.16. The vaccine formulation of claim 14, further comprising a deliveryagent.
 17. The vaccine formulation of claim 16, wherein the deliveryagent is a mucoadhesive.
 18. The vaccine formulation of claim 17,wherein the mucoadhesive is selected from the group consisting ofglycosaminoglycans, carbohydrate polymers, polyvinyl alcohol, polyvinylpyrollidone, polysaccharides, polyions, cellulose derivatives, proteins,and deoxyribonucleic acid.
 19. The vaccine formulation of claim 18,wherein the mucoadhesive is a polysaccharide.
 20. The vaccineformulation of claim 19, wherein said polysaccharide is chitosan,chitosan salt, or chitosan base.
 21. The vaccine formulation of claim14, wherein the vaccine formulation is a liquid formulation.
 22. Thevaccine formulation of claim 14, wherein the vaccine formulation is adry powder formulation.
 23. The dry powder formulation of claim 22 incombination with one or more devices for administering one or more dosesof said formulation.
 24. The dry powder formulation of claim 23, whereinsaid one or more doses are unit doses.
 25. The dry powder formulation ofclaim 23, wherein the device is a single-use nasal administrationdevice.
 26. The vaccine formulation of claim 11, wherein saidformulation is administered to a subject by a route selected from thegroup consisting of mucosal, intramuscular, intravenous, subcutaneous,intradermal, subdermal, and transdermal routes of administration. 27.The vaccine formulation of claim 26, wherein said mucosal administrationis intranasal, oral, or vaginal.
 28. The vaccine formulation of claim27, wherein the formulation is in the form of a nasal spray, nasal dropsor dry powder.
 29. A method of inducing a protective immunity to a viralinfection in a subject comprising administering to the subject thevaccine formulation of claim
 11. 30. The method of claim 29, wherein theviral infection is a Norovirus infection.
 31. The method of claim 30,wherein said vaccine formulation confers protection from one or moresymptoms of Norovirus infection.
 32. A method of making a virus-likeparticle comprising: aligning amino acid sequences of capsid proteinsfrom two or more circulating strains of a non-enveloped virus;determining a consensus sequence from said aligned amino acid sequences;preparing a composite sequence based on said consensus sequence thatcontains at least 1 different amino acid as compared to each of thecapsid sequences of said two or more circulating strains; and expressingsaid composite sequence in a host cell, thereby producing a virus-likeparticle.
 33. The method of claim 32, wherein the non-enveloped virus isa Calicivirus.
 34. The method of claim 33, wherein the Calicivirus is aNorovirus or Sapovirus.
 35. The method of claim 34, wherein theNorovirus is a genogroup I or genogroup II Norovirus.